EXHIBIT 10.5
                                                                    ------------

 
                             EMPLOYMENT AGREEMENT
                             --------------------


          THIS EMPLOYMENT AGREEMENT (the "Agreement"), entered into September
22, 1997, by and among McKesson Corporation, a Delaware corporation (the
"Company"), AmeriSource Corporation, a Delaware corporation ("Patriot") and R.
David Yost (the "Executive"), effective as of the Effective Time.
 
          WHEREAS, the Executive is presently employed by Patriot as President
and CEO; and
 
          WHEREAS, the Company, Patriot and a wholly-owned subsidiary of the
Company ("Newco") have entered into an Agreement and Plan of Merger, dated
September 22, 1997 (the "Merger Agreement"), pursuant to which Newco will be
merged with and into Patriot at the Effective Time (as defined in the Merger
Agreement), with Patriot thereafter becoming a wholly-owned subsidiary of the
Company; and
 
          WHEREAS, each of the Company and Patriot has determined that it is in
its best interest and the best interests of its shareholders that the Company
retain the services of the Executive on and following the Effective Time; and
 
          WHEREAS, the Executive is willing to provide services to the Company
on the terms and conditions set forth in this Agreement;
 
          NOW THEREFORE, in consideration of the mutual covenants contained
herein, the parties hereby agree as follows:
 
          1.   Employment.  The Company agrees to employ the Executive, and the
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Executive agrees to be employed by the Company, upon the terms and conditions
hereinafter provided in this Agreement, for a period commencing at the Effective
Time and continuing for three years thereafter (the "Term"); provided, however,
that this Agreement shall be of no force and effect unless and until the Closing
(as defined in the Merger Agreement) occurs.

          2.   Position and Duties.  During the Term, the Company agrees to
               -------------------                                         
employ the Executive to serve in such executive capacities as may be assigned to
him from time to time by the Company's Chief Executive Officer (the "CEO").
Without limiting the generality of the foregoing, the Executive shall initially
serve

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as Group President of the Company's Patriot Services Group and Corporate Vice
President of the Company, and, in such position, Executive will direct the
integration of the Company and Patriot. Thereafter, the Executive shall perform
such other executive services as may be assigned to him from time to time by the
CEO. During the Term, and except for illness or incapacity and reasonable
vacation periods of no more than four weeks in any calendar year (or such other
period as shall be consistent with the Company's policies for other key
executives), the Executive shall devote all of his business time, attention,
skill and efforts exclusively to the business and affairs of the Company and its
affiliates; provided, however, that the Executive may serve on other boards as a
director or trustee, with the prior approval of the CEO, if such service does
not interfere with his ability to discharge his duties and responsibilities to
the Company.

          3.   Compensation.  For all services rendered by the Executive in any
               ------------                                                    
capacity required hereunder during the Term, including, without limitation,
services as an executive, officer, director, or member of any committee of the
Company, or any subsidiary, affiliate or division thereof, the Executive shall
be compensated as follows:

               (a)  Base Salary. The Company shall pay the Executive a fixed
                    -----------
salary of $350,000 per annum or such higher annual amount as may be paid from
time to time pursuant to the terms hereof ("Base Salary"). The Base Salary shall
be subject to such periodic review (which shall occur in accordance with Company
policy) and such periodic increases as the Compensation Committee of the Board
of Directors of the Company shall deem appropriate in accordance with the
Company's customary procedures and practices regarding the salaries of senior
officers, provided, that the annual adjustment shall be no less than the
increase in the "Consumer Price Index" now known as the Consumer Price Index for
Urban Wage Earners and Clerical Workers, All Items, Philadelphia, Pennsylvania
(1967=100), as published by the Bureau of Labor, Statistics, United States
Department of Labor. Base Salary shall be payable in accordance with the
customary payroll practices of the Company.

               (b)  Bonus Awards.  The Executive shall be entitled to receive an
                    ------------
annual incentive cash compensation award under the Company's policy of providing
for the payment of incentive cash compensation to key officers based upon the
performance of the Company and the officer's individual performance.

               (c)  Stock Options and Restricted Stock Awards.
                    ----------------------------------------- 

                    (i) Subject to the terms and conditions of the

                                       2

 
          Company's 1994 Stock Option and Restricted Stock Plan (the "Plan"), at
          the Effective Time, the Company and the Executive will enter into the
          Stock Option Award Agreement annexed hereto as Exhibit A. The options
          granted pursuant to such agreement shall vest and become exercisable
          in installments of twenty-five percent per year commencing on the
          first anniversary following the Effective Time, provided that the
          Executive is employed by the Company or any of its affiliates on each
          such anniversary date. If the Company terminates Executive's
          employment during the Term due to a Without Cause Termination, all
          such options shall vest and become immediately exercisable for ninety
          days following the date of such termination, after which date all
          options shall lapse. Upon a Termination for Cause of the Executive by
          the Company during the Term, all such options, whether or not
          previously vested, shall immediately lapse.

                    (ii)   Subject to the terms and conditions of the Plan, at
          the Effective Time, the Company and the Executive will enter into the
          Restricted Stock Grant Agreement annexed hereto as Exhibit B.
          Restrictions on such restricted shares shall lapse on the second
          anniversary following the Effective Time, so long as, on such date,
          the Company and the Executive agree that the Executive has satisfied
          such performance goals as may be mutually agreed upon by the Executive
          and the CEO. If the Company terminates Executive's employment during
          the Term due to a Without Cause Termination, all restrictions on such
          shares shall immediately lapse, provided that such performance goals
          have been satisfied as of the date of termination. Upon a Termination
          for Cause of the Executive by the Company during the Term, all such
          shares, whether or not previously vested, shall be immediately
          forfeited.

                    (iii)  In addition to the grants set forth in Sections
          3(c)(i) and 3(c)(ii) of this Section 3, the Executive shall, on and
          following the Effective Time, be eligible for consideration for stock
          option grants and restricted stock awards at such times as other
          similarly situated executives, in accordance with the Company's
          customary practice.

               (d)  Supplemental Insurance. The Executive shall be entitled to
                    ----------------------     
such split dollar life insurance policy as was in place between Patriot

                                       3

 
and the Executive prior to December 31, 1996.

               (e)  Additional Benefits. Except as modified by this Agreement,
                    -------------------
the Executive shall be entitled to participate in all compensation or employee
benefit plans or programs (other than termination pay programs), and to receive
all benefits, perquisites and emoluments, for which salaried employees of the
Company are generally eligible under any plan or program now or hereafter
established and maintained by the Company for senior officers, to the fullest
extent permissible under the general terms and provisions of such plans or
programs and in accordance with the provisions thereof, including, if available,
group hospitalization, health, dental care, life or other insurance, tax-
qualified pension, savings, thrift and profit-sharing plans, sick-leave plans,
travel or accident insurance, disability insurance, automobile allowance or
automobile lease plans, and executive contingent compensation plans, including,
without limitation, if available, capital accumulation programs and stock
purchase, restricted stock and stock option plans. Notwithstanding the
foregoing, nothing in this Agreement shall preclude the amendment or termination
of any such plan or program, provided that such amendment or termination is
applicable generally to the senior officers of the Company or any subsidiary or
affiliate.

               (f) Perquisites.  Executive shall be entitled for each complete
                   -----------                                                
twelve-month period that this Agreement is in effect to reimbursement of tax
planning and tax preparation charges, not to exceed $5,000, and to reimbursement
of club dues, not to exceed $10,000.

          4.   Business Expenses.  The Company shall pay or reimburse the
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Executive for all reasonable travel or other expenses incurred by the Executive
(and his spouse where there is a legitimate business reason for his spouse to
accompany him) in connection with the performance of his duties and obligations
under this Agreement, including, without limitation, expenses for entertainment,
travel (including automobile operating expenses), meals, hotel accommodations
and the like, in accordance with such rules and policies relating thereto as the
Company may from time to time adopt.  Reimbursement shall be subject to the
Executive's presentation of appropriate vouchers in accordance with such
procedures as the Company may from time to time establish for senior officers
and to preserve any deductions for federal income taxation purposes to which the
Company may be entitled.

          5.   Housing Loan and Assistance.
               --------------------------- 

               (a)  At or following the Effective Time, upon Executive's
relocation to San Francisco, California, the Company shall make a housing loan
to

                                       4

 
the Executive in the sum of $500,000 (the "Housing Loan"). The Housing Loan
shall be evidenced by a promissory note (the "Note") in form provided by the
Company, and shall be secured by a deed of trust on Executive's principal
residence (the "Property"). The Housing Loan shall be without interest prior to
"Maturity" (as defined in the Note) and shall be repaid to the Company in full
upon the earliest to occur of any of the following: (i) 60 days after
termination of Executive's employment for any reason, (ii) sale or other
transfer of ownership of the Property, (iii) use of the Property other than as a
principal residence, or (iv) 10 years from the date of the Housing Loan.

               (b)  Subject to Section 5(c) of this Section 5, the Company shall
establish a deferred compensation account on behalf of the Executive in the
Company's Deferred Compensation Administration Plan, and, so long as Executive
remains in the employment of the Company, the Company shall credit to such
account the amount of $50,000 per annum commencing on the first anniversary of
the Housing Loan, continuing for the duration of Executive's employment through
the tenth anniversary of such date (or a pro rata portion of such amount if the
employment of the Executive is terminated during any such year).  Such account
shall bear interest each year at the rate established by the Board of Directors
of the Company (the "Board") (or any duly authorized committee thereof).  The
balance of such account shall be released to Executive (or, at the Company's
sole election, applied against the balance, if any of the Housing Loan) upon the
earlier of (i) the Maturity of the Housing Loan following Executive's
termination of employment with the Company, or (ii) ten years from the date of
the first credit to such account.

               (c)  Notwithstanding any other provision of this Section 5, if
Executive's employment is terminated for any reason prior to the fifth
anniversary of the date of the Housing Loan, Executive shall forfeit the entire
sum of such account.

               (d)  The Company shall reimburse the Executive, in accordance
with its existing policies, for the following reasonable expenses incurred in
connection with sale of his current residence and purchase of suitable housing
in San Francisco, California: real estate brokerage fees, pest control
inspections, title insurance and escrow fees and moving costs (including
temporary living expenses, if any, while in transit). In addition, the Company
shall reimburse the Executive in an amount up to one-half month of Base Salary
for non-receipted, miscellaneous moving expenses.

          6.   Effect of Termination of Employment.
               ----------------------------------- 

                                       5

 
               (a)  Termination by the Company During Term. If the Company
                    --------------------------------------
terminates Executive's employment during the Term due to a Without Cause
Termination, the Company shall provide Severance Benefits to the Executive.

               (b)  Termination by the Executive During Term.  If the Executive
                    ----------------------------------------
terminates his employment during the thirty days commencing immediately
following the second anniversary date of the Effective Time, the Company shall
provide Severance Benefits to the Executive.

               (c)  All Other Terminations. Upon all terminations other than the
                    ----------------------
terminations referred to in Sections 6(a) and 6(b) of this Section 6 (including,
but not limited to, voluntary retirement and termination upon or following
expiration of the Term), earned but unpaid Base Salary as of the date of
termination of employment shall be paid to the Executive in full, and the
Company shall have no obligation to provide Severance Benefits. In addition, the
Executive shall receive the benefits, if any, to which he is entitled as a
former employee under the employee benefit programs and compensation plans and
programs maintained for the benefit of the Company's officers and employees.

               (d)  Immediately upon termination of the Executive's employment
for any reason, Executive shall voluntarily resign from the Board.

               (e)  Definitions.  For purposes of this Agreement, the following
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terms have the following meanings:

                    (i)    The term "Termination for Cause" shall mean
          termination of the Executive's employment by the Company upon (i)
          Executive's misconduct, habitual neglect, dishonesty or other knowing
          and material violation of the Company's policies and procedures in
          effect from time to time, (ii) actions (or failures to act) by
          Executive in bad faith and to the detriment of the Company or any of
          its affiliates or (iii) a material breach by the Executive of one or
          more terms of this Agreement.

                    (ii)   The term "Without Cause Termination" shall mean a
          termination of the Executive's employment by the Company, upon 30
          days' notice to the Executive, other than a Termination for Cause.

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                    (iii)  The term "Severance Benefits" shall mean:

                    (A)    the Executive's earned but unpaid Base Salary as of
the date of termination of employment;
 
                    (B)    the benefits, if any, to which the Executive is
entitled as a former employee under the employee benefit programs and
compensation plans and programs maintained for the benefit of the Company's
officers and employees;

                    (C)    continued coverage under the Company's employee
welfare benefit plans (including, but not limited to, group hospitalization,
health, dental care, life or other insurance, travel or accident insurance and
disability insurance) for three years following the date of termination, with
coverage equivalent to the coverage to which the Executive would have been
entitled had the Executive continued in employment with the Company during such
three years at the highest annual rate of Base Salary achieved during the
Executive's period of actual employment with the Company; provided, however,
that the Executive may, upon written notice to the Company, elect to receive the
present value of such coverage in cash in a lump sum; and

                    (D)    an amount equal to three times the sum of the highest
Base Salary in effect during the Term and highest bonus paid to the Executive by
either the Company or Patriot in any of the four years prior to the date of
termination, payable in a lump sum as soon as is practicable following
termination.
 
Payment of Severance Benefits shall be in lieu of any severance, termination or
similar payment that would otherwise be due to the Executive under any other
severance program, plan or practice of the Company or its subsidiaries and
affiliates.  Upon commencement of payment of Severance Benefits, the Executive
shall not be entitled to any other payment or benefit under this Agreement.
 
               (f)  Excise Tax Limitation.
                    --------------------- 

                    (i)  Notwithstanding anything contained in this Agreement to
          the contrary, to the extent that the payments and benefits provided
          under this Agreement and benefits provided to, or for the benefit of,
          the Executive under any other Company plan or agreement (such payments
          or benefits are collectively referred to as the "Payments") would be
          subject to the excise tax (the "Excise Tax") imposed under Section
          4999 of the Internal Revenue Code of

                                       7

 
          1986, as amended (the "Code"), the Payments shall be reduced (but not
          below zero) if and to the extent necessary so that no Payment to be
          made or benefit to be provided to the Executive shall be subject to
          the Excise Tax (such reduced amount is hereinafter referred to as the
          "Limited Payment Amount"). Unless the Executive shall have given prior
          written notice specifying a different order to the Company to
          effectuate the foregoing, the Company shall reduce or eliminate the
          Payments, by first reducing or eliminating the portion of the Payments
          which are not payable in cash and then by reducing or eliminating cash
          payments, in each case in reverse order beginning with payments or
          benefits which are to be paid the farthest in time from the
          Determination (as hereinafter defined). Any notice given by the
          Executive pursuant to the preceding sentence shall take precedence
          over the provisions of any other plan, arrangement or agreement
          governing the Executive's rights and entitlements to any benefits or
          compensation.

                    (ii) The determination of whether the Payments shall be
          reduced to the Limited Payment Amount pursuant to this Agreement and
          the amount of such Limited Payment Amount shall be made, at the
          Company's expense, by an accounting firm selected by the Company which
          is one of the six largest accounting firms in the United States (the
          "Accounting Firm").  The Accounting Firm shall provide its
          determination (the "Determination"), together with detailed supporting
          calculations and documentation, to the Company and the Executive
          within ten (10) days of the date of termination of the Executive, if
          applicable, or such other time as requested by the Company or by the
          Executive (provided the Executive reasonably believes that any of the
          Payments may be subject to the Excise Tax).

          7.   Other Duties of Executive During and After Term.
               ----------------------------------------------- 

               (a)  Confidential Information. Executive acknowledges that by
                    ------------------------ 
reason of his employment with the Company and Patriot he has and will hereafter,
from time to time during the Term, become exposed to and become knowledgeable
about proposals, plans inventions, practices, systems, programs, formulas,
processes, methods, techniques, research, records, supplier sources, customer
lists, and other forms of business information regarding the Company and its
affiliates which are not known to the Company's competitors and which are not
recognized as being encompassed within standard business or management practices
and which are kept secret and confidential by the Company (the

                                       8

 
"Confidential Information"). Executive therefore agrees that at no time during
or after the period of his employment by the Company will he disclose or use the
Confidential Information except, during his employment, as may be required in
the prudent course of business for the benefit of the Company.

               (b)  Non-Compete. In consideration of the covenants of the
                    -----------
Company and the Executive hereunder, Executive hereby agrees that, until the
latest of: (i) while Executive is employed during the Term, (ii) during such
time after the Term as Executive is employed by the Company, (iii) while
Executive is receiving Severance Benefits pursuant to this Agreement, or (iv)
for a period of one year after Executive's termination of employment for any
reason, he will not, unless authorized in writing to do so by the Company,
directly or indirectly own, manage, operate, join, control or participate in the
ownership, management, operation or control of, or be employed by or otherwise
connected in any manner with any business which directly or indirectly competes
with any line of business of the Company or any of its affiliates; provided,
that nothing in this paragraph shall prohibit Executive after termination of his
employment from acquiring up to 5% of any class of outstanding equity securities
of any corporation whose equity securities are regularly traded on a national
securities exchange or in the over-the-counter market. Executive agrees that for
a period ending on the second anniversary after Executive's termination of
employment hereunder for any reason, Executive will not (x) recruit any employee
of the Company or any of its affiliates or solicit or induce, or attempt to
solicit or induce, any employee of the Company or any of its affiliates to
terminate his or her employment with, or otherwise cease his or her relationship
with, the Company or any of its affiliates, or (y) solicit, divert or take away,
or attempt to solicit, divert or take away, the business or patronage of any of
the clients, customers or accounts, or prospective clients, customers or
accounts, of the Company or any of its affiliates that were contracted,
solicited or served by the Executive while employed by the Company or any of its
affiliates.

               (c)  Remedies. The Company and Executive confirm that the
                    --------
restrictions contained in Sections 7(a) and 7(b) of this Agreement are, in view
of the nature of the business of the Company and its affiliates, reasonable and
necessary to protect the legitimate interests of the Company and its affiliates
and that any violation of any provision of Section 7(a) or 7(b) will result in
irreparable injury to the Company and its affiliates. Executive hereby agrees
that, in the event of any breach or threatened breach of the terms or conditions
of this Agreement by Executive, the Company's remedies at law will be inadequate
and, in any such event, the Company shall be entitled to preliminary or
permanent injunctive relief and other equitable relief in any court of competent
jurisdiction. Executive further

                                       9

 
irrevocably consents to the jurisdiction of any Pennsylvania state court or
federal court located in the Commonwealth of Pennsylvania over any suit, action
or proceeding arising out of or relating to this Section 7 and hereby waives, to
the fullest extent permitted by law, any objection that he may now or hereafter
have to such jurisdiction or to the laying of venue of any such suit, action or
preceding has been brought in an inconvenient forum. This Section 7 of this
Agreement shall (x) survive the termination of this Agreement and continue
throughout the duration of the Executive's employment with the Company, except
as amended or modified by written agreement of the parties and (y) survive the
Executive's termination of employment with the Company for any reason.

               (d)  Modification of Terms. If any restriction in this Section 7
                    ---------------------
of this Agreement is adjudicated to exceed the time, geographic, service or
other limitations permitted by applicable law in any jurisdiction, the Executive
agrees that such may be modified and narrowed, either by a court or the Company,
to the maximum time, geographic, service or other limitations permitted by
applicable law so as to preserve and protect the Company's legitimate business
interest, without negating or impairing any other restrictions or undertaking
set forth in this Agreement.

          8.   Withholding Taxes.   The Company may directly or indirectly
               -----------------                                          
withhold from any payments made under this Agreement all federal, state, city or
other taxes as shall be required pursuant to any law or governmental regulation
or ruling.

          9.   Consolidation, Merger, or Sale of Assets.  Nothing in this
               ----------------------------------------                  
Agreement shall preclude the Company from consolidating or merging into or with,
or transferring all or substantially all of its assets to, another corporation
which assumes this Agreement and all obligations and undertakings of the Company
hereunder.  Upon such a consolidation, merger or transfer of assets and
assumption, the terms "Company" as used herein shall mean such other corporation
and this Agreement shall continue in full force and effect.

          10.  No Attachment.  Except as required by law, no right to receive
               -------------                                                 
payments under this Agreement shall be subject to anticipation, commutation,
alienation, sale, assignment, encumbrance, charge, pledge, or hypothecation or
to execution, attachment, levy, or similar process or assignment by operation of
law, and any attempt, voluntary or involuntary, to effect any such action shall
be null, void and of no effect; provided, however, that nothing in this Section
10 shall preclude the assumption of such rights by executors,

                                       10

 
administrators or other legal representatives of the Executive or his estate and
their assigning any rights hereunder to the person or persons entitled thereto.

          11.  No Mitigation.  The Executive shall not be required to mitigate
               -------------                                                  
the amount of any payment or benefit provided for in this Agreement by seeking
other employment or otherwise, nor shall the amount of any payment or benefit
provided for in this Agreement be reduced by any compensation earned by other
employment or otherwise.

          12.  Source of Payment.  All payments provided for under this
               -----------------                                       
Agreement shall be paid in cash from the general funds of the Company.  The
Company shall not be required to establish a special or separate fund or other
segregation of assets to assure such payments, and, if the Company shall make
any investments to aid it in meeting its obligations hereunder, the Executive
shall have no right, title or interest whatever in or to any such investments
except as may otherwise be expressly provided in a separate written instrument
relating to such investments.  To the extent that any person acquires a right to
receive payments from the Company hereunder, such right, without prejudice to
rights which employees may have, shall be no greater than the right of an
unsecured creditor of the Company.

          13.  Severability.  If any provision of the Agreement or application
               ------------                                                   
thereof to anyone or under any circumstances is adjudicated to be invalid or
unenforceable in any jurisdiction, such invalidity or unenforceability shall not
affect any other provision or application and shall not invalidate or render
unenforceable such provision or application in any other jurisdiction.

          14.  Contents of Agreement.  At the Effective Time, without any
               ---------------------                                     
further action by the parties, this Agreement shall supersede all prior
agreements between the Executive and Patriot and shall set forth the entire
understanding among the parties hereto with respect to the subject matter
hereof.  This Agreement may not be changed, modified, extended or terminated
except upon written amendment approved by the parties hereto.  Without limiting
the generality of the foregoing, at the Effective Time, the Employment
Agreement, effective as of August 1, 1997, between the Executive and Patriot,
shall be terminated without any liability of Patriot or the Company thereunder
except for accrued and unpaid base salary and business expenses (if any) as of
the date of termination.

                                       11

 
          15.  Governing Law.  The validity, interpretation, performance, and
               -------------                                                 
enforcement of this Agreement shall be governed by the laws of the Commonwealth
of Pennsylvania, and Executive consents to the jurisdiction of the state and
federal courts of Pennsylvania in any dispute arising under this Agreement.

          16.  Survival.  Any section of this Agreement which provides a benefit
               --------                                                         
to the Executive and which does not expressly provide for its termination upon
the expiration of the Term shall survive the expiration of the Term, and the
obligation to provide benefits to the Executive as set forth in such section
shall remain binding upon the Company until such time as the Executive's
employment relationship with the Company is terminated and the benefits provided
under such section are paid in full to the Executive.

          17.  Miscellaneous.  All section headings are for convenience only.
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This Agreement may be executed in any number of counterparts, each of which when
executed shall be deemed to be an original and all of which together shall be
deemed to be one and the same instrument.  It shall not be necessary in marking
proof of this Agreement or any counterpart hereof to produce or account for any
of the other counterparts.

          18.  Arbitration.  Except with respect to actions for preliminary and
               -----------                                                     
permanent injunctive relief and other equitable relief under Section 7, any
controversy or claim arising out of or relating to this Agreement, or any breach
thereof, shall be settled by arbitration in accordance with the rules of the
American Arbitration Association, and judgment upon such award rendered by the
arbitrator(s) may be entered in any court having jurisdiction thereof.  The
arbitration shall be held in Philadelphia, Pennsylvania, unless another location
shall be mutually agreed to by the parties at the time of the arbitration.  If
Section 6(f) is not applicable, in any dispute between the parties as to which
Executive is sustained on the claims(s) by or against him, the Company shall pay
all reasonable legal fees incurred by Executive in connection with the dispute
over such claim(s).  If more than one claim is involved in any dispute and if
Executive is sustained as to one or more of such claims but not as to all of
such claims, there shall be a reasonable allocation of applicable reasonable
legal expenses.  The Company will reimburse Executive for those reasonable legal
expenses determined by the arbitrator(s) or by the consent of the parties to be
allocable to the claim or claims as to which Executive is upheld.


     IN WITNESS WHEREOF, and intending to be legally bound, the Company and
Patriot have caused this Agreement to be executed by duly authorized officers,

                                       12

 
and the Executive has signed this Agreement this 22nd day of September, 1997,
effective as of the Effective Time.

                                   McKESSON CORPORATION

                                   By:    /s/  Ivan D. Meyerson
                                          ---------------------------  
                                   Name:  Ivan D. Meyerson
                                   Title: Vice President


                                   AMERISOURCE CORPORATION

                                   By:    /s/  Kurt J. Hilzinger
                                          ----------------------
                                   Name:  Kurt J. Hilzinger
                                   Title: Senior Vice President and    
                                          Chief Financial Officer 
                                                            
                                                            
                                   /s/  R. David Yost
                                   ------------------
                                   R. David Yost

183534.08

                                       13

 
                   Exhibit A - Stock Option Award Agreement
                   ----------------------------------------


                       NOTICE OF GRANT OF STOCK OPTIONS
                              AND GRANT AGREEMENT

ID:

The following option grant has been awarded to you to purchase McKesson
Corporation Common Stock:

          Non-Qualified Stock Option Grant No.     ______________            
          Date of Grant                            [Closing Date]        
          Stock Option Plan                        1994                  
          Option Price per Share                   [FMV on Date of Grant]
          Total Number of Shares Granted           50,000                
          Total Price of Shares Granted            ____________             

You hereby accept the grant of this option subject to the terms and
conditions of the Employment Agreement between you and McKesson
Corporation, dated September __, 1997, and, to the extent not
inconsistent with such Employment Agreement, subject to the terms of
this Agreement, the 1994 Stock Option and Restricted Stock Plan
("Plan") and the Statement of Terms and Conditions Applicable to Stock
Options Granted under the Plan, incorporated herein by reference, and
further acknowledge receipt of copies of such documents, if they have
not already been provided to you. PLEASE RETAIN THIS INFORMATION FOR
YOUR FILES. You should consult your tax advisor concerning the
appropriate reporting requirements regarding this grant. This option
vests and becomes exercisable at the rate of 25% per year beginning
one year after the date of grant.

Please sign the copy of this Agreement and return it to Dana T.
Iapicca, One Post Street, 29/th/ Floor, San Francisco, CA 94104.

___________________________________       _____________________________ 
For McKesson Corporation                       Date

___________________________________       _____________________________  
Optionee                                       Date



 
            Exhibit B - Restricted Stock Grant Agreement
            --------------------------------------------


                  RESTRICTED STOCK GRANT AGREEMENT
                              UNDER THE
                        McKESSON CORPORATION
             1994 STOCK OPTION AND RESTRICTED STOCK PLAN

     The Compensation Committee of the Board of Directors has approved a grant
to you of 20,000 shares of Restricted Stock (the "Stock") pursuant to the
McKesson Corporation 1994 Stock Option and Restricted Stock Plan (the "Plan"),
and subject to the terms and conditions of the Employment Agreement between you
and the McKesson Corporation, dated September __, 1997.  A certificate for the
Stock has been issued to you effective [as of the Closing Date] and will be
released to you on the second anniversary of the date of grant, i.e., on
[______________], subject to the restrictions set forth in your Employment
Agreement and, to the extent not inconsistent with your Employment Agreement, in
the Plan and the Statement of Terms and Conditions Applicable to Shares of
Restricted Stock Granted pursuant to the 1994 Stock Option and Restricted Stock
Plan, copies of which are attached hereto and incorporated herein by reference,
unless already provided to you.

     Please acknowledge your acceptance of this grant by signing your name in
the space provided on the photocopy of this Grant Agreement and return the
photocopy to Dana T. Iapicca, Assistant Secretary, McKesson Corporation, One
Post Street, Suite 2950, San Francisco, CA  94104.

     If you elect to recognize gross income on the Stock in the year of grant,
please telephone Dana Iapicca (415-983-8367) for information and a Section 83(b)
election form.

MCKESSON CORPORATION


By:________________________       _________________________
                                            Date

___________________________       _________________________
         Grantee                             Date