Exhibit 10.34

                               REPURCHASE AGREEMENT


     THIS AGREEMENT made and entered into as of this 1st day of April, 1999, 
by and between GalaGen Inc. ("GalaGen") and Chiron Corporation ("Chiron").

                                   WITNESSETH

     WHEREAS, GalaGen has heretofore issued to Chiron three Warrants to 
purchase shares of Common Stock of GalaGen, each dated March 29, 1995 (the 
"Warrants");

     WHEREAS, Chiron is currently the registered holder of the Warrants;

     WHEREAS, Chiron desires that GalaGen repurchase the Warrants on the 
terms set forth in this Agreement, and GalaGen desires to repurchase the 
Warrants on such terms;

     NOW THEREFORE, in consideration of the mutual agreements set forth in 
this Agreement and for good and valuable other consideration, the receipt and 
sufficiency of which are hereby acknowledged, the parties hereto hereby agree 
as follows:

     1.   REPURCHASE AND SALE OF THE WARRANTS.  Subject to the terms and 
conditions hereinafter set forth, and in reliance on the representations and 
warranties of GalaGen contained herein, Chiron hereby agrees to sell to 
GalaGen the Warrants in their entirety, for an aggregate cash purchase price 
equal to $375,000.  The aggregate cash purchase price set forth in the 
immediately preceding sentence is hereinafter sometimes referred to as the 
"Warrant Repurchase Price."  Subject to the terms and conditions hereinafter 
set forth, and in reliance on the representations and warranties of Chiron 
contained herein, GalaGen hereby agrees to repurchase from Chiron the 
Warrants in their entirety by payment of the Warrant Repurchase Price.

     2.   SURRENDER OF DOCUMENTS.  On the Closing Date, upon payment by 
GalaGen of the Warrant Repurchase Price, Chiron shall surrender and deliver 
to GalaGen the original Warrants together with completed Forms of Assignment 
in the forms attached to the Warrants naming GalaGen as assignee.

     3.   CLOSING DATE.  Subject to the terms and conditions of this 
Agreement, the closing of the repurchase and sale of the Warrants (the 
"Closing") shall be held at the offices of GalaGen in Arden Hills, Minnesota 
as soon as practicable after the execution and delivery by both parties of 
this Agreement, or at such other time and/or on such other date and/or at 
such other place as the parties hereto may mutually agree (the date of 
Closing being herein referred to as the "Closing Date", which may be the same 
as the date of this Agreement).  On the Closing Date, GalaGen shall wire 
transfer, or cause to be wire transferred, to the account 



of Chiron Corporation, account no. 14725-00611 at Bank of America - San 
Francisco, ABA# 121000358, in immediately available funds, the Warrant 
Repurchase Price, and Chiron shall simultaneously surrender and deliver to 
GalaGen the documents referred to in paragraph 2.

     4.   REPRESENTATIONS AND WARRANTIES OF CHIRON.  Chiron represents and 
warrants to GalaGen as follows:

          4.1  CORPORATE EXISTENCE AND POWER. Chiron is a corporation duly 
organized, validly existing and in good standing under the laws of the State 
of Delaware and has all corporate power necessary to complete the sale of the 
Warrants to GalaGen pursuant to the terms of this Agreement and to perform 
its other obligations under this Agreement.

          4.2  CORPORATE AUTHORIZATION.  The execution, delivery and 
performance by Chiron of this Agreement have been duly authorized by all 
necessary corporate action on the part of Chiron.  This Agreement constitutes 
the valid and binding agreement of Chiron enforceable against Chiron in 
accordance with its terms, except as (i) the enforceability of this Agreement 
may be limited by bankruptcy, insolvency, moratorium or other similar laws 
affecting the enforcement of creditors' rights generally and (ii) the 
availability of equitable remedies may be limited by equitable principles of 
general applicability.

          4.3  GOVERNMENTAL AUTHORIZATION.  The execution, delivery and 
performance by Chiron of this Agreement require no action by or in respect 
of, or filing with, any governmental body, agency or official, except for 
filings with the Securities and Exchange Commission ("SEC") which may be 
required of Chiron with respect to Chiron's ownership interest in Galagen.

          4.4  NON-CONTRAVENTION.  The execution, delivery and performance by 
Chiron of this Agreement do not and will not (i) violate the certificate of 
incorporation or bylaws of Chiron, (ii) violate any applicable statute, law, 
rule, regulation, ordinance, judgment, ruling by a court, writ, injunction, 
order or decree, or (iii) require any consent or other action by, or any 
notice to, any person or entity under, or constitute a default or create a 
penalty under, conflict with or give rise to any right of termination, 
cancellation or acceleration of any right or obligation of Chiron under, any 
agreement, contract, lease, license or other instrument binding upon or 
applicable to Chiron.

          4.5  REPRESENTATIONS REGARDING WARRANTS.  Chiron is the record and 
beneficial owner of the Warrants, free and clear of any pledge, lien, 
security interest or other encumbrance, restriction or adverse claim (a 
"Lien"), and no Lien will arise as a result of the sale of the Warrants.  The 
Warrants have not been altered since the original receipt thereof, except as 
set forth in the Warrants, there are no limitations upon the right of Chiron 
to sell the Warrants to GalaGen; and except as set forth in this Agreement, 
Chiron has not granted any right to any other person or entity to acquire the 
Warrants.  Chiron has the right to 

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surrender and deliver the Warrants to GalaGen upon receipt of the Warrant 
Repurchase Price.  No affiliate of Chiron has any right, title or interest in 
the Warrants.

          4.6  LITIGATION.  There is no action, suit, investigation or 
proceeding pending against or, to the knowledge of Chiron, threatened against 
or affecting, Chiron or any affiliate of Chiron before any court or 
arbitrator or any governmental body, agency or official as of the date of 
this Agreement which in any manner challenges or seeks to prevent, enjoin, 
alter or delay the transactions contemplated by this Agreement.

     5.   REPRESENTATIONS AND WARRANTIES OF GALAGEN.  GalaGen represents and 
warrants to Chiron as follows:

          5.1  CORPORATE EXISTENCE AND POWER.  GalaGen is a corporation duly 
organized, validly existing and in good standing under the laws of the State 
of Delaware and has all corporate power necessary to repurchase the Warrants 
pursuant to the terms of this Agreement and perform its other obligations 
under this Agreement.

          5.2  CORPORATE AUTHORIZATION.  The execution, delivery and 
performance by GalaGen of this Agreement have been duly authorized by all 
necessary corporate action on the part of GalaGen.  This Agreement 
constitutes the valid and binding agreement of GalaGen enforceable against 
GalaGen in accordance with its terms, except as (i) the enforceability of 
this Agreement may be limited by bankruptcy, insolvency, moratorium or other 
similar laws affecting the enforcement of creditors' rights generally and 
(ii) the availability of equitable remedies may be limited by equitable 
principles of general applicability.

          5.3  GOVERNMENTAL AUTHORIZATION.  The execution, delivery and 
performance by GalaGen of this Agreement require no action by or in respect 
of, or filing with, any governmental body, agency or official, provided that 
this Agreement may have to be filed with the Securities and Exchange 
Commission following the repurchase of the Warrants.

          5.4  NON-CONTRAVENTION.  The execution, delivery and performance by 
GalaGen of this Agreement do not and will not (i) violate the certificate of 
incorporation or bylaws of GalaGen, (ii) violate any applicable statute, law, 
rule, regulation, ordinance, judgment, ruling by a court, writ, injunction, 
order or decree or (iii) require any consent or other action by, or any 
notice to, any person or entity under, or constitute a default or create a 
penalty under, conflict with or give rise to any right of termination, 
cancellation or acceleration of any right or obligation of GalaGen under, any 
agreement, contract, lease, license or other instrument binding upon or 
applicable to GalaGen, provided that this Agreement may have to be filed with 
the Securities and Exchange Commission following the repurchase of the 
Warrants.

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          5.5  LITIGATION.  There is no action, suit, investigation or 
proceeding pending against, or, to the knowledge of GalaGen, threatened 
against or affecting, GalaGen before any court or arbitrator or any 
governmental body, agency or official as of the date of this Agreement which 
in any manner challenges or seeks to prevent, enjoin, alter or delay the 
transactions contemplated by this Agreement.

     6.   SURVIVAL OF REPRESENTATIONS AND WARRANTIES.  The representations 
and warranties contained in Sections 4 and 5 hereof shall survive the Closing 
and continue indefinitely and shall be enforceable against the party making 
the representations and warranties by the party for whose benefit they are 
made. Such representations and warranties shall each be deemed to be 
representations and warranties made as of the Closing Date (as well as the 
date of this Agreement) unless an officer of the party making them shall 
deliver a certificate to the contrary to the other party hereto prior to the 
Closing.

     7.   CONDITIONS TO OBLIGATIONS.

          7.1  CONDITIONS TO OBLIGATIONS OF CHIRON AND GALAGEN.  The 
obligations of Chiron and GalaGen to consummate the Closing are subject to 
the satisfaction of the condition that no provision of any applicable law or 
regulation and no judgment, injunction, order or decree shall prohibit the 
consummation of the Closing.

          7.2  CONDITIONS TO OBLIGATION OF GALAGEN.  The obligation of 
GalaGen to consummate the Closing is subject to the satisfaction of the 
following further conditions:

          (i)   the representations and warranties of Chiron contained in
     this Agreement shall be true in all material respects at and as of the
     Closing Date as if made at and as of such date.

          (ii)  GalaGen shall have received the Warrants.

          7.3. CONDITIONS TO OBLIGATION OF CHIRON.  The obligation of Chiron 
to consummate the Closing is subject to the satisfaction of the following 
further conditions:

          (i)   the representations and warranties of GalaGen contained in
     this Agreement shall be true in all material respects at and as of the
     Closing Date as if made at and as of such date.

          (ii)  Chiron shall have received the Warrant Repurchase Price.

     8.   MISCELLANEOUS.

          8.1  AMENDMENTS AND WAIVERS.  Any provision of this Agreement may 
be amended or waived if, but only if, such amendment or waiver is in writing 
and is signed, in 

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the case of an amendment, by each party to this Agreement, or in the case of 
a waiver, by the party against whom the waiver is to be effective.

          8.2  EXPENSES.  All costs and expenses incurred in connection with 
this Agreement shall be paid by the party incurring such cost or expense.

          8.3  SUCCESSORS AND ASSIGNS.  The provisions of this Agreement 
shall be binding upon and inure to the benefit of the parties hereto and 
their respective successors and permitted assigns; provided that no party may 
assign, delegate or otherwise transfer any of its rights or obligations under 
this Agreement without the consent of the other party hereto.

          8.4  ENTIRE AGREEMENT.  This Agreement constitutes the entire 
agreement between the parties hereto regarding the subject matter hereof.  

          8.5  GOVERNING LAW.  This Agreement shall be governed by and 
construed in accordance with the law of the State of Delaware, without regard 
to the conflicts of law rules of such state.

          8.6  COUNTERPARTS.  This Agreement may be executed in two or more 
counterparts, each of which shall be deemed to be an original but all of 
which shall constitute one instrument.

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be 
duly executed by their respective authorized officers as of the day and year 
first above written.

                                       GALAGEN INC.

                                       By   /s/  ROBERT A. HOERR
                                           -------------------------------
                                           Its   Chairman & CEO
                                                --------------------------



                                       CHIRON CORPORATION

                                       By  /s/ James E. Kent
                                           -------------------------------
                                           Its   V.P., Treasurer
                                                --------------------------




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