Exhibit 4.1

                           MOLECULAR BIOSYSTEMS, INC.

                    1997 OUTSIDE DIRECTORS STOCK OPTION PLAN

                                    Article 1

                           PURPOSE AND EFFECTIVE DATE

        1.1  Purpose.  The purpose of the Plan is to permit the Company to grant
stock  options to its outside  directors to reward them for their efforts on the
Company's  behalf and to provide an  additional  incentive to  contribute to the
attainment of the Company's long-term plans and objectives.

        1.2 Effective Date. The Plan shall become effective if and when approved
by the Company's shareholders at the 1997 Annual Meeting of Shareholders.

        1.3 Term.  The Plan shall have a term of 10 years  expiring on the tenth
anniversary of its effective date. No Option may be granted under the Plan after
its expiration.


                                    Article 2

                                   DEFINITIONS

        2.1  Annual   Meeting   means  the  annual   meeting  of  the  Company's
shareholders.

        2.2 Board means the Company's Board of Directors. If the Board delegates
its authority to  administer  the Plan to a committee of the Board in accordance
with Article 4,  references  to the "Board"  shall be construed as references to
the committee.

        2.3   Common Stock means shares of the Company's common stock, $.01 par
 value.

        2.4   Company means Molecular Biosystems, Inc., a Delaware corporation.

        2.5   Director means a director of the Company.

        2.6 Expiration Date is defined in Paragraph 5.3.

        2.7 Grant Date is defined in Paragraph 5.1.

        2.8 Officer  means:  (i) the  Company's  Chairman of the Board and Chief
Executive  Officer;  (ii) the Company's  President and Chief Operating  Officer;
(iii)  any Vice  President  of the  Company;  and (iv) any other  person  who is
considered an "officer" of the Company for purposes of Rule  16a-1(f)  under the
Securities Exchange Act of 1934.






        2.9   Option is defined in Paragraph 5.1.

      2.10 Option Agreement is defined in Paragraph 5.6.

      2.11  Outside  Director  means a Director who is neither an Officer nor an
employee  of the  Company or any  corporation  in which the  Company  owns stock
possessing  at least 50% of the total  combined  voting  power of all classes of
stock.

      2.12    Plan means this stock  option  plan,  as it may be  amended.  The
name of the Plan is the  "Molecular Biosystems, Inc. 1997 Outside Directors 
Stock Option Plan."


                                    Article 3

                           TYPE AND NUMBER OF OPTIONS

        3.1  Type  of  Options.   The  Options   granted  under  this  Plan  are
nonstatutory stock options.

        3.2 Maximum  Number of Options.  The maximum  number of shares of Common
Stock for which  Options  may be granted is 300,000  (subject to  adjustment  as
provided in Paragraph 7.1). If any Option expires  unexercised or is surrendered
prior to the Plan's  expiration,  the number of Underlying  Shares in respect of
the Option shall be added back to the number of shares of Common Stock for which
Options may be granted  under the Plan.  The  Underlying  Shares to be delivered
upon the exercise of an Option may be either  authorized but unissued  shares or
issued shares reacquired by the Company (or any combination of the two).


                                    Article 4

                                 ADMINISTRATION

         The Plan shall be  administered  by the Board.  Subject to the  express
provisions  of the Plan,  the Board may  interpret  the Plan,  adopt and  revise
policies and  procedures to  administer  the Plan,  and make all  determinations
required for the Plan's administration.  The actions of the Board shall be final
and binding.  The Board may delegate its authority to its Executive Committee or
to  another  committee  appointed  by  the  Board  consisting  of at  least  two
Directors.


                                    Article 5

                                  STOCK OPTIONS

         5.1  Option Grants.

         (a)  Annual  Grant.  On the last  business  day in  March of each  year
              (beginning with March 1997) (the "Grant Date"),  the Company shall
              grant  each  incumbent  Outside  Director  who was  elected at the
              preceding  Annual  Meeting  an option  for 6,500  shares of Common
              Stock (an  "Option").  No Option  shall be granted to an incumbent
              Outside  Director  who was not  elected  at the  preceding  Annual
              Meeting but was subsequently  elected or appointed by the Board to
              fill a vacancy.

         (b)  Discretionary  Grant.  The Board shall have the authority to grant
              options to an Outside  Director in amounts greater than the annual
              grant  to  that  Outside  Director  set  forth  in  the  preceding
              subparagraph,  provided that no Outside Director shall be entitled
              to receive  Options for more than 21,500 shares of Common Stock in
              any  fiscal  year.  The date on which the Board  acts to grant any
              such options shall be the Grant Date.

         5.2  Exercise  Price.  The  exercise  price of each Option shall be the
closing  price of the Company's  Common Stock on the New York Stock  Exchange on
the Grant Date (or on the last trading day preceding the Grant Date if it is not
a trading day).

         5.3 Term.  Each Option shall have a 10-year term  expiring on the tenth
anniversary  of the  Grant  Date  (the  "Expiration  Date")  (subject  to  early
expiration as provided in Paragraph  5.4). The Board shall determine (i) whether
each  Option  shall be  exercisable  in full at one time or in  installments  at
different  times and (ii) the time or times at which the Option or  installments
shall become exercisable. No Option or installment shall be exercisable prior to
the  first  anniversary  of the Grant  Date,  except  as its  exercisability  is
accelerated by the Board.  The Board may accelerate  the  exercisability  of any
Option or installment at any time.

         5.4 Death of Outside  Director.  The failure of the Outside Director to
whom an Option was  granted to remain an  Outside  Director  shall not cause the
Option to expire or  otherwise  terminate;  but in the event of the death of the
Outside Director (whether or not he or she is then an incumbent  Director),  the
Option shall expire on the earlier of (i) the first  anniversary  of the Outside
Director's death or (ii) the Option's Expiration Date.

         5.5 Transferability.  No Option may be transferred, assigned or pledged
(whether by  operation of law or  otherwise),  except as provided by will or the
applicable  intestacy  laws,  and no  Option  shall  be  subject  to  execution,
attachment or similar process. An Option or Installment may be exercised only by
Outside Director to whom it was granted, except in the case of his or her death,
when it may be  exercised  by the person or persons to whom it passes by will or
inheritance.

         5.6 Option  Agreements.  Each Option  shall be  evidenced  by a written
agreement (an "Option Agreement"), in a form approved by the Board, entered into
by the Company and the Outside Director to whom the Option is granted.


                                    Article 6

                               EXERCISE OF OPTIONS

         6.1 Manner of Exercise.  An exercisable Option may be exercised in full
or in part (but only in  respect of a whole  number of  shares)  by (i)  written
notice to the Board (or its  designee)  stating  the  number of shares of Common
Stock in respect of which the Option is being exercised and (ii) full payment of
the exercise price of those shares.

         6.2  Payment of Exercise  Price.  Payment of the  exercise  price of an
Option shall be made by certified or bank cashier's check or by wire transfer of
immediately  available  funds  or, if  permitted  by the  Board  (either  in the
applicable  Option  Agreement  or at the time of  exercise):  (i) by  delivering
shares of Common Stock having a fair market value on the date of exercise  equal
to the  exercise  price;  (ii) by directing  the Company to  withhold,  from the
shares of Common Stock otherwise issuable upon exercise of the Option, shares of
Common  Stock  having a fair market  value on the date of exercise  equal to the
exercise  price;  (iii) by  surrendering  exercisable  Options which have a fair
market value on the date of exercise equal to the exercise price  (measuring the
fair market value of the Options  surrendered by the excess of (y) the aggregate
fair market value on the date of exercise of the shares of Common Stock issuable
upon exercise of the Option over (z) the aggregate exercise price);  (iv) by any
combination of the preceding  methods of payment;  or (v) by any other method of
payment  authorized by the Board.  For purposes of this  Paragraph and Paragraph
6.3),  "fair market value" shall be determined by the closing price of shares of
the  Company's  Common Stock on the date in question (or on the last trading day
preceding the date in question if it is not a trading day).

         6.3 Withholding. Each Outside Director exercising an Option shall remit
to the Company an amount sufficient to satisfy the Company's federal,  state and
local withholding tax obligation in connection with the exercise.  Payment shall
be made by certified or bank cashier's  check or by wire transfer of immediately
available  funds or, if permitted by the Board (either in the applicable  Option
Agreement or at the time of  exercise),  by either one or both of the  following
methods:  (i) by delivering shares of Common Stock having a fair market value on
the date of exercise equal to the Company's withholding  obligation;  or (ii) by
directing  the Company to withhold,  from the shares of Common  Stock  otherwise
issuable  upon  exercise of the  Option,  shares of Common  Stock  having a fair
market  value  on the  date  of  exercise  equal  to the  Company's  withholding
obligation.






                                    Article 7

                            MISCELLANEOUS PROVISIONS

         7.1  Capitalization  Adjustments.  The  aggregate  number  of shares of
Common  Stock for which  Options may be granted  under the Plan,  the  aggregate
number of  Underlying  Shares in respect  of each  outstanding  Option,  and the
exercise  price of each such Option may be adjusted by the Board as it considers
appropriate  in the event of  changes  in the  number of  outstanding  shares of
Common  Stock by reason of stock  dividends,  stock  splits,  recapitalizations,
reorganizations and the like. Adjustments under this Paragraph 7.1 shall be made
in the Board's discretion, and its decisions shall be final and binding.

         7.2  Amendment  and  Termination.  The  Board  may  amend,  suspend  or
terminate  the Plan at any  time;  but  except  to comply  with  changes  in the
Internal  Revenue  Code of 1986 and the  related  regulation,  the Board may not
amend the Plan more once every six months to change: (i) the number of shares of
Common Stock for which Options may be granted under the Plan;  (ii) the benefits
under the Plan; or (iii) the eligibility requirements of the Plan. The Company's
shareholders  shall be  required to approve  any such  amendment  (other than an
amendment  authorized  under Paragraph 7.1) that would  materially  increase the
number of shares,  materially  increase  the benefits or  materially  change the
eligibility requirements.  If the Plan is terminated, the provisions of the Plan
shall  continue  to apply  to  Options  granted  prior  to  termination,  and no
amendment,  suspension or  termination  of the Plan shall  adversely  affect the
rights of an Outside  Director in respect of any Option held  without his or her
consent.

         7.3 Compliance  with Section 16(b).  The Plan shall be interpreted  and
administered  in a manner that  satisfies the  applicable  requirements  of Rule
16b-3  under the  Securities  Exchange  Act so that  Outside  Directors  will be
entitled to the benefits of Rule 16b-3.

         7.4 No  Right  To  Nomination.  Nothing  in the  Plan or in any  Option
Agreement  shall  confer on any  Outside  Director  the right to  continue to be
nominated for election as a Director.
         7.5  Notices.  Notices  required or  permitted  under the Plan shall be
considered  to have been duly  given if sent by  certified  or  registered  mail
addressed  to the Board at the  Company's  principal  office  or to any  Outside
Director at his or her address as it appears on the Company's records.

         7.6  Severability.  If any  provision  of the Plan is held  illegal  or
invalid  for any  reason,  the  illegality  or  invalidity  shall not affect the
remaining provisions, and the Plan shall be construed and administered as if the
illegal or invalid provision had not been included.

         7.7 Governing Law. The Plan and all Option Agreements shall be governed
in accordance with the laws of the State of California.