THIS NOTE IS SUBJECT TO THE TERMS AND  CONDITIONS  OF THAT CERTAIN
      SUBORDINATION  AGREEMENT  DATED  AS OF  AUGUST  7,  1997,  BY  AND
      BETWEEN THE LENDER NAMED BELOW AND FOOTHILL CAPITAL CORPORATION.


 
                               PROMISSORY NOTE


$125,000.00                                                 St. Louis, Missouri
                                                            August 7, 1997

            FOR VALUE RECEIVED,  the undersigned,  ALLIED HEALTHCARE PRODUCTS,
INC.,  a  Delaware  corporation,   B&F  MEDICAL  PRODUCTS,  INC.,  a  Delaware
corporation,  BEAR MEDICAL SYSTEMS, INC., a California  corporation,  HOSPITAL
SYSTEMS,  INC.,  a California  corporation,  LIFE  SUPPORT  PRODUCTS,  INC., a
California   corporation,   BICORE  MONITORING  SYSTEMS,  INC.,  a  California
corporation,  each with their chief executive  office located at 1720 Sublette
Avenue, St. Louis, Missouri,  63110 (collectively  "Borrowers") HEREBY JOINTLY
AND  SEVERALLY  PROMISE  TO PAY to the  order  of  DONALD  E.  NICKELSON  (the
"Lender") in lawful money of the United  States of America,  the principal sum
of  ONE  HUNDRED  TWENTY-FIVE  THOUSAND  AND  NO/100  DOLLARS   ($125,000.00),
together with interest  thereon from the date hereof at a fixed rate per annum
equal to fourteen  percent  (14%),  compounded  semi-annually.  Principal  and
interest shall be due and payable as follows:

      (a)   Interest  shall be due on the  first  Business  Day of each  month
(for the immediately preceding month),  computed through the last calendar day
of  the  preceding  month,  and  on  the  Maturity  Date.  Interest  shall  be
calculated  on a daily basis  (computed  on the actual  number of days elapsed
over a year of 360 days),  commencing on the date hereof  (including the first
day but excluding the last day); and

      (b)   Principal  shall  be due  and  payable  on  the  earlier  of:  (a)
February 7, 1998 or thirty  (30) days  thereafter  if  extended in  accordance
with the Purchase  Agreement (the "Maturity  Date"),  or (b) the occurrence of
an  Event  of  Default  (as  defined  in  the  hereinafter   defined  Purchase
Agreement).
 
      This  Promissory  Note ("Note") is the  Promissory  Note referred to in,
and is issued  under the terms of, and  pursuant  to, the  provisions  of that
certain Note Purchase  Agreement between the Lender and the Borrowers dated as
of August 7, 1997 (as the same may be amended,  restated,  extended,  replaced
or otherwise  modified  from time to time,  the "Purchase  Agreement")  and is
entitled to all of the benefits and  security of the Purchase  Agreement.  All
of the terms,  covenants and  conditions of the Purchase  Agreement and of the
other  instruments  evidencing  or securing  the  indebtedness  hereunder  are
hereby  made a part of  this  Note  and  incorporated  herein  in full by this
reference.  All capitalized terms used herein,  unless otherwise  specifically
defined  in this  Note,  shall  have the same  meanings  as given  them in the
Purchase Agreement.




      If any payment of  principal  or interest due on this Note is payable on
a day other than a Business  Day,  then such payment shall be made on the next
Business Day.

      If any Event of Default  shall occur and shall not have been waived in a
writing given by the Lender to the Borrowers,  then the outstanding  principal
balance of this Note  shall bear  interest  from and after the  occurrence  of
such Event of Default at the Default Rate until the principal  balance of this
Note is paid in full.

      Borrowers  shall  prepay  this  Note at the time and in the  manner  set
forth in the Purchase  Agreement.  Borrowers  may wholly  prepay this Note and
make  partial  prepayments  hereon in whole  multiples  of $1,000 from time to
time,  without  penalty or premium,  but only if (i) the Borrowers give Lender
written  notice  of their  intention  to make  such  prepayment  at least  one
Business Day prior to tendering  the  prepayment,  and (ii)  Borrowers pay any
accrued and unpaid interest on the Note to the date of such payment.

      The  earlier  of the  Maturity  Date or the  occurrence  of an  Event of
Default  under the Purchase  Agreement  shall  constitute  an event of default
under this Note and shall  entitle the Lender,  at its option,  to declare the
then  outstanding  principal  balance and accrued  interest thereon to be, and
the same shall  thereupon  become,  immediately due and payable without notice
to or demand upon the Borrowers,  all of which the Borrowers  hereby expressly
waive.

      Time is of the  essence of this Note.  To the fullest  extent  permitted
by  applicable  law,  the  Borrowers,  for  themselves  and  their  respective
successors and assigns,  expressly waive presentment,  demand, protest, notice
of dishonor,  notice of  non-payment,  notice of maturity,  notice of protest,
presentment   for  the  purpose  of   accelerating   maturity,   diligence  in
collection, and the benefit of any exemption or insolvency laws.

      Wherever  possible each  provision of this Note shall be  interpreted in
such a manner as to be effective  and valid under  applicable  law, but if any
provision of this Note shall be prohibited or invalid  under  applicable  law,
such  provision  shall be  ineffective  to the extent of such  prohibition  or
invalidity  without  invalidating the remainder of such provision or remaining
provisions  of this  Note.  No delay or  failure  on the part of the Lender in
the  exercise  of any  right or remedy  hereunder  shall  operate  as a waiver
thereof,  nor as an  acquiescence  in any  default,  nor shall  any  single or
partial  exercise  by the  Lender of any right or  remedy  preclude  any other
right or remedy.  The Lender,  at its option,  may enforce its rights  against
any  collateral  securing this Note without  enforcing its rights  against the
Borrowers,  any guarantor of the  indebtedness  evidenced  hereby or any other
property  or  indebtedness  due  or  to  become  due  to  the  Borrowers.  The
Borrowers agree that, without releasing or impairing any Borrowers'  liability
hereunder,  the  Lender  may at any time  release,  surrender,  substitute  or
exchange  any  collateral  securing  this Note and may at any time release any
party primarily or secondarily  liable for the indebtedness  evidenced by this
Note.  No  amendment,  modification  or waiver of any  provision of this Note,
nor consent to any  departure  by any  Borrower  herefrom,  shall be effective
unless  the same  shall be in  writing  signed  by an  authorized  officer  of
Lender,  and then only in the specific  instance and for the purpose for which
given.
 
                                      2


In the event that any payment of any principal or interest due  hereunder  shall
not be paid  when  due,  whether  by  reason  of  acceleration,  termination  or
otherwise,  and this Note is placed in the hands of an attorney or attorneys for
collection or for foreclosure of any agreement,  document or instrument securing
payment hereof or for  representation of Lender in connection with bankruptcy or
insolvency  proceedings  relating  hereto,  each Borrower  jointly and severally
promises  to pay, in addition to all other  amounts  otherwise  due hereon,  all
costs  and  expenses  of  such  collection,   foreclosure  and   representation,
including,  without limitation,  reasonable attorneys' fees, expert witness fees
and all other  costs  and  expenses  paid or  incurred  by Lender in  connection
therewith (whether or not litigation shall be commenced in aid thereof).

      All  notices  required  to be given or which may be given in  connection
with this Note shall be given in the manner  required  for  notices  under the
Purchase Agreement.

      This Note is governed by and shall be  interpreted  in  accordance  with
the internal laws of the State of Missouri,  without regard to conflict of law
rules.

     [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK; SIGNATURE PAGES FOLLOW]

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      IN WITNESS  WHEREOF,  each  Borrower has caused this Note to be executed
and  delivered  by its duly  authorized  representative  as of the date  first
above written.

                                    ALLIED HEALTHCARE PRODUCTS, INC.


                                         /s/ Barry F. Baker
                                    By:  ______________________________
                                         Name: Barry F. Baker
                                         Title: Vice President-Finance
ATTEST:

By:    ___________________________        
Name:  ___________________________        
Title: ___________________________        

                                    B&F MEDICAL PRODUCTS, INC.

                                  
                                         /s/ Barry F. Baker
                                    By:  ______________________________
                                         Name: Barry F. Baker
                                         Title: Vice President-Finance
ATTEST:

By:    ___________________________        
Name:  ___________________________
Title: ___________________________

                                    BEAR MEDICAL SYSTEMS, INC.

                                  
                                         /s/ Barry F. Baker
                                    By:  ______________________________
                                         Name: Barry F. Baker
                                         Title: Vice President-Finance
ATTEST:

By:    ___________________________
Name:  ___________________________
Title: ___________________________


                                    HOSPITAL SYSTEMS, INC.

                                  
                                         /s/ Barry F. Baker
                                    By:  ______________________________
                                         Name: Barry F. Baker
                                         Title: Vice President-Finance
ATTEST:

By:    ___________________________
Name:  ___________________________
Title: ___________________________


                                       4


                                    LIFE SUPPORT PRODUCTS, INC.

                                  
                                         /s/ Barry F. Baker
                                    By:  ______________________________
                                         Name: Barry F. Baker
                                         Title: Vice President-Finance
ATTEST:

By:    ___________________________
Name:  ___________________________
Title: ___________________________


                                    BICORE MONITORING SYSTEMS, INC.


                                  
                                         /s/ Barry F. Baker
                                    By:  ______________________________
                                         Name: Barry F. Baker
                                         Title: Vice President-Finance
ATTEST:

By:    ___________________________
Name:  ___________________________
Title: ___________________________


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