FIFTH AMENDMENT OF ISOLYSER COMPANY, INC.
                                STOCK OPTION PLAN

         WHEREAS,  by at least a majority vote of the holders of the outstanding
capital stock of Isolyser Company, Inc. (the "Company") who voted on said matter
at the annual  shareholders  meeting of the Company held on April 28, 1992,  the
Company approved,  ratified and affirmed that certain Stock Option and Alternate
Rights Plan (as amended to date, the "Plan"); and

         WHEREAS,  by at least a majority vote of the holders of the outstanding
capital stock of the Company who voted on said matter at the annual shareholders
meetings of the Company held (i) on April 19, 1994, the Company amended the Plan
to increase  the number of shares  reserved for options and subject to alternate
rights under the Plan from 1,400,000  shares of common stock to 1,566,076 shares
of common stock (as adjusted for the Company's October 2, 1995 two for one stock
split) and to change the name of the Plan to "Stock Option Plan",  (ii) on April
27, 1995, the Company amended the Plan to increase the number of shares reserved
for options and subject to  alternate  rights  under the Plan from  1,566,076 to
2,400,000 shares of common stock (as adjusted for the Company's  October 2, 1995
two for one stock  split),  and (iii) on May 16, 1996,  the Company  amended the
Plan to  increase  the number of shares  reserved  for  options  and  subject to
alternate  rights under the Plan from  2,400,000  to 3,600,000  shares of common
stock; and

         WHEREAS,  the Board of Directors has resolved to further amend the Plan
as hereinbelow more particularly set forth.

         NOW, THEREFORE, the Plan is hereby amended as follows:

1.   Defined Terms.  Initially capitalized terms used in this Amendment which
are not  otherwise  defined  by this  Amendment  are used with the same  meaning
ascribed to such terms in the Plan.

2.       Amendment.

         (a)  The last sentence of Section 2.1(e) of the Plan is hereby deleted.

         (b)  Section  5.1 of  the  Plan  is  amended  by  deleting  the  number
"3,600,000"  (such figure having been adjusted to reflect the Company's  October
2, 1995 two for one stock split) appearing therein and inserting in lieu thereof
the number  "4,400,000"  (such  figure  having  been  adjusted  to  reflect  the
Company's October 2, 1995 two for one stock split).

         (c)  Section  9.1 of the Plan is  amended by  inserting  "Except as may
otherwise be provided by the  Committee,  ..." at the beginning of the first two
sentences of such Section.

         (d)      Article XII, Section (a) of the Plan is hereby deleted.


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3. Effectiveness.  Section 2(a) of this Amendment shall be effective on the date
of  this  Amendment.  Sections  2(b)-(d)  of this  Amendment  shall  not  become
effective  unless and until such  provisions are approved by at least a majority
vote of the holders of the outstanding  capital stock of the Company present, or
represented,  and  entitled to vote on such matter at a meeting of  shareholders
duly called and  convened  within one (1) year  following  the date  hereof.  In
addition,  Section 2(b) of this Amendment shall not become  effective unless and
until the transactions contemplated by that certain Agreement and Plan of Merger
dated as of March 15, 1996 and  subsequently  amended,  among the  Company,  MMI
Merger Corp. and Microtek Medical, Inc. shall have been consummated.

4.  Ratification.  Except  as  hereinabove  amended  and  modified,  the Plan is
approved, ratified and affirmed without further modification or amendment.

         IN WITNESS  WHEREOF,  the Company has caused this Fifth Amendment to be
executed on July 17, 1996,  in  accordance  with Article XII of the Plan and the
authority provided by the Board of Directors.

                                    ISOLYSER COMPANY, INC.



                                    By:
                                    Name:  C. Fred Harlow
                                    Title: Senior Vice President and Chief
                                             Financial Officer

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