<PAGE>

                                                                    EXHIBIT 4.34
                                      WARRANT

                   TO SUBSCRIBE FOR AND PURCHASE COMMON STOCK OF

                                    GALAGEN INC.


          THIS WARRANT CERTIFIES THAT, for value received, Henry J. Cardello 
(herein called "Purchaser") or registered assigns is entitled to subscribe 
for and purchase from GalaGen Inc. (herein called the "Company"), a 
corporation organized and existing under the laws of the State of Delaware, 
at the price specified below (subject to adjustment as noted below) at any 
time from and after September 30, 1998 to and including September 30, 2003, 
Twelve Thousand Five Hundred (12,500) fully paid and nonassessable shares of 
the Company's Common Stock, $.01 par value per share ("Common Stock") 
(subject to adjustment as noted below).

          The warrant purchase price shall be $1.813 per share (subject to 
adjustment as noted below).

          This Warrant is subject to the following provisions, terms and 
conditions:

          1.   The rights represented by this Warrant may be exercised by the 
holder hereof, in whole or in part, by written notice of exercise, in the 
form attached hereto, delivered to the Company ten days prior to the intended 
date of exercise and by the surrender of this Warrant (properly endorsed if 
required) at the principal office of the Company and upon payment to it by 
check of the purchase price in lawful money of the United States.  The 
Company agrees that the shares so purchased shall be and are deemed to be 
issued to the holder hereof as the record owner of such shares as of the 
close of business on the date on which this Warrant shall have been 
surrendered and payment made for such shares as aforesaid.  Subject to the 
provisions of the next succeeding paragraph, certificates for the shares of 
stock so purchased shall be delivered to the holder hereof within a 
reasonable time, not exceeding l0 days, after the rights represented by this 
Warrant shall have been so exercised, and, unless this Warrant has expired, a 
new Warrant representing the number of shares, if any, with respect to which 
this Warrant shall not then have been exercised shall also be delivered to 
the holder hereof within such time.

          2.   Notwithstanding the foregoing, however, the Company shall not 
be required to deliver any certificate for shares of stock upon exercise of 
this Warrant except in accordance with the provisions, and subject to the 
limitations, of paragraph 7 hereof and the restrictive legend under the 
heading "Restriction on Transfer" below.

          3.   The Company covenants and agrees that all shares which may be 
issued upon the exercise of the rights represented by this Warrant will, upon 
issuance, be duly authorized and issued, fully paid and nonassessable.  The 
Company further covenants and agrees that during the period within which the 
rights represented by this Warrant may be 

<PAGE>

exercised, the Company will at all times have authorized, and reserved for 
the purpose of issue or transfer upon exercise of the subscription rights 
evidenced by this Warrant, a sufficient number of shares of its Common Stock 
to provide for the exercise of the rights represented by this Warrant.

          4.   The above provisions are, however, subject to the following:

          (a)  The warrant purchase price shall, from and after the date of 
issuance of this Warrant, be subject to adjustment from time to time as 
hereinafter provided.  Upon each adjustment of the warrant purchase price, 
the holder of this Warrant shall thereafter be entitled to purchase, at the 
warrant purchase price resulting from such adjustment, the number of shares 
obtained by multiplying the warrant purchase price in effect immediately 
prior to such adjustment by the number of shares purchasable pursuant hereto 
immediately prior to such adjustment and dividing the product thereof by the 
warrant purchase price resulting from such adjustment.

          (b)  In case the Company shall (i) declare a dividend upon the 
Common Stock payable in Common Stock (other than a dividend declared to 
effect a subdivision of the outstanding shares of Common Stock, as described 
in paragraph (c) below) or any obligations or any shares of stock of the 
Company which are convertible into or exchangeable for Common Stock (any of 
such obligations or shares of stock being hereinafter called "Convertible 
Securities"), or in any rights or options to purchase Common Stock or 
Convertible Securities, or (ii) declare any other dividend or make any other 
distribution upon the Common Stock payable otherwise than out of earnings or 
earned surplus, then thereafter the holder of this Warrant upon the exercise 
hereof will be entitled to receive the number of shares of Common Stock to 
which such holder shall be entitled upon such exercise, and, in addition and 
without further payment therefor, each dividend described in clause (i) above 
and each dividend or distribution described in clause (ii) above which such 
holder would have received by way of dividends or distributions if 
continuously since such holder became the record holder of this Warrant such 
holder (x) had been the record holder of the number of shares of Common Stock 
then received, and (y) had retained all dividends or distributions in stock 
or securities (including Common Stock or Convertible Securities, and any 
rights or options to purchase any Common Stock or Convertible Securities) 
payable in respect of such Common Stock or in respect of any stock or 
securities paid as dividends or distributions and originating directly or 
indirectly from such Common Stock.  For the purposes of the foregoing, a 
dividend or distribution other than in cash shall be considered payable out 
of earnings or earned surplus only to the extent that such earnings or earned 
surplus are charged an amount equal to the fair value of such dividend or 
distribution as determined by the Board of Directors of the Company.

          (c)  In case the Company shall at any time subdivide its 
outstanding shares of Common Stock into a greater number of shares, the 
warrant purchase price in effect immediately prior to such subdivision shall 
be proportionately reduced, and conversely, in case the outstanding shares of 
Common Stock of the Company shall be combined into a 


                                      -2-

<PAGE>

smaller number of shares, the warrant purchase price in effect immediately 
prior to such combination shall be proportionately increased.

          (d)  If any capital reorganization or reclassification of the 
capital stock of the Company, or consolidation or merger of the Company with 
another corporation, or sale of all or substantially all of its assets to 
another corporation (any such reorganization, reclassification, 
consolidation, merger or sale being hereinafter called an "Event") shall be 
effected in such a way that holders of Common Stock shall be entitled to 
receive stock, securities or assets with respect to or in exchange for Common 
Stock, then, unless lawful and adequate provision shall have been made 
whereby the holder hereof shall thereafter have the right to purchase and 
receive, upon the basis and upon the terms and conditions specified in this 
Warrant and in lieu of the shares of the Common Stock of the Company 
immediately theretofore purchasable and receivable upon the exercise of the 
rights represented hereby, such shares of stock, securities or assets as may 
be issued or payable with respect to or in exchange for a number of 
outstanding shares of Common Stock of the Company equal to the number of 
shares of such stock immediately theretofore purchasable and receivable upon 
the exercise of the rights represented hereby had the Event not taken place, 
the Board of Directors of the Company shall declare, at least twenty days 
prior to the actual effective date of the Event, and provide written notice 
to the holder hereof of the declaration, that this Warrant shall be canceled 
at the time of, or immediately prior to the occurrence of, the Event (unless 
it shall have been exercised prior to the occurrence of the Event) in 
exchange for payment to the holder hereof, within twenty days after the 
Event, of cash equal to the amount (if any), for each share of Common Stock 
issuable upon exercise of this Warrant, by which the Event Proceeds per share 
of Common Stock (as hereinafter defined) exceeds the purchase price per share 
of Common Stock under this Warrant.  In the event of a declaration pursuant 
to this paragraph (d), this Warrant, if not exercised prior to the Event, 
shall be canceled at the time of, or immediately prior to, the Event, as 
provided in the declaration, subject to the payment obligations of the 
Company provided in this paragraph (d).  For purposes of this paragraph (d), 
"Event Proceeds per share of Common Stock" shall mean the cash plus the fair 
market value, as determined in good faith by the Board of Directors of the 
Company, of the non-cash consideration to be received per share of Common 
Stock by the shareholders of the Company upon the occurrence of the Event. If 
provision shall be made, pursuant to this paragraph (d), for the right of the 
holder hereof to purchase and receive stock, securities or assets of any 
successor corporation (other than the Company) upon the occurrence of any 
Event, then such successor corporation shall assume, by written instrument 
executed and mailed to the registered holder hereof at the last address of 
such holder appearing on the books of the Company, the obligation to deliver 
to such holder such shares of stock, securities or assets as, in accordance 
with the foregoing provisions, such holder may be entitled to purchase.

          (e)  Upon any adjustment of the warrant purchase price, then and in 
each such case the Company shall give written notice thereof, by first-class 
mail, postage prepaid, addressed to the registered holder of this Warrant at 
the address of such holder as shown on the books of the Company, which notice 
shall state the warrant purchase price resulting from 


                                      -3-

<PAGE>

such adjustment and the increase or decrease, if any, in the number of shares 
purchasable at such price upon the exercise of this Warrant, setting forth in 
reasonable detail the method of calculation and the facts upon which such 
calculation is based.

          (f)  In case any time:

          (1)  the Company shall declare any cash dividend on Common Stock
     at a rate in excess of the rate of the last cash dividend theretofore
     paid;

          (2)  the Company shall pay any dividend payable in stock upon
     Common Stock or make any distribution (other than regular cash
     dividends) to the holders of Common Stock;

          (3)  the Company shall offer for subscription pro rata to the
     holders of Common Stock any additional shares of stock of any class or
     other rights;

          (4)  there shall be any capital reorganization, or
     reclassification of the capital stock of the Company, or consolidation
     or merger of the Company with, or sale of all or substantially all of
     its assets to, another corporation; or

          (5)  there shall be a voluntary or involuntary dissolution,
     liquidation or winding up of the Company;

then, in any one or more of said cases, the Company shall give written 
notice, by first-class mail, postage prepaid, addressed to the registered 
holder of this Warrant at the address of such holder as shown on the books of 
the Company, of the date on which (aa) the books of the Company shall close 
or a record shall be taken for such dividend, distribution or subscription 
rights, or (bb) such reorganization, reclassification, consolidation, merger, 
sale, dissolution, liquidation or winding up shall take place, as the case 
may be.  Such notice shall also specify the date as of which the holders of 
Common Stock of record shall participate in such dividend, distribution or 
subscription rights, or shall be entitled to exchange their Common Stock for 
securities or other property deliverable upon such reorganization, 
reclassification, consolidation, merger, sale, dissolution, liquidation or 
winding up, as the case may be.  Such written notice shall be given at least 
20 days prior to the action in question and not less than 20 days prior to 
the record date or the date on which the Company's transfer books are closed 
in respect thereto.

          (g)  If any event occurs as to which in the opinion of the Board of 
Directors of the Company the other provisions of this paragraph 4 are not 
strictly applicable or if strictly applicable would not fairly protect the 
purchase rights of the holder of this Warrant or of Common Stock in 
accordance with the essential intent and principles of such provisions, then 
the Board of Directors shall make an adjustment in the application of such 
provisions, in accordance with such essential intent and principles, so as to 
protect such purchase rights as aforesaid; provided, however, that the 
members of the Board of Directors of the Company shall not be liable to the 
holders hereof for any such determination made in good faith.


                                      -4-

<PAGE>

          (h)  No fractional shares of Common Stock shall be issued upon the 
exercise of this Warrant, but, instead of any fraction of a share which would 
otherwise be issuable, the Company shall pay a cash adjustment (which may be 
effected as a reduction of the amount to be paid by the holder hereof upon 
such exercise) in respect of such fraction in an amount equal to the same 
fraction of the market price per share of Common Stock as of the close of 
business on the date preceding the written notice of exercise required by 
paragraph 1 above. "Market price" for purposes of this paragraph 4(h) shall 
mean, if the Common Stock is traded on a securities exchange or on The Nasdaq 
National Market, the closing price of the Common Stock on such exchange or 
The Nasdaq National Market, or, if the Common Stock is otherwise traded in 
the over-the-counter market, the closing bid price, in each case averaged 
over a period of 20 consecutive business days prior to the date as of which 
"market price" is being determined.  If at any time the Common Stock is not 
traded on an exchange or The Nasdaq National Market, or otherwise traded in 
the over-the-counter market, the "market price" shall be deemed to be the 
higher of (i) the book value thereof as determined by any firm of independent 
public accountants of recognized standing selected by the Board of Directors 
of the Company as of the last day of any month ending within 60 days 
preceding the date as of which the determination is to be made, or (ii) the 
fair value thereof determined in good faith by the Board of Directors of the 
Company as of a date which is within l5 days of the date as of which the 
determination is to be made.

          5.   As used herein, the term "Common Stock" shall mean and include 
the Company's presently authorized Common Stock and shall also include any 
capital stock of any class of the Company hereafter authorized which shall 
not be limited to a fixed sum or percentage in respect of the rights of the 
holders thereof to participate in dividends or in the distribution of assets 
upon the voluntary or involuntary liquidation, dissolution or winding up of 
the Company; provided that the shares purchasable pursuant to this Warrant 
shall include shares designated as Common Stock of the Company on the date of 
original issue of this Warrant or, in the case of any reclassification of the 
outstanding shares thereof, the stock, securities or assets provided for in 
paragraph 4(d) above.

          6.   This Warrant shall not entitle the holder hereof to any voting 
rights or other rights as a stockholder of the Company.

          7.(a)     The holder of this Warrant acknowledges that neither this 
Warrant nor any of the shares of Common Stock issuable upon exercise hereof 
have been registered under the Securities Act of 1933, as amended (the 
"Act"), or any state securities laws and that this Warrant or such shares of 
Common Stock may only be transferred in accordance with this paragraph 7.  
The holder of this Warrant, by acceptance hereof, represents that it has 
acquired this Warrant for investment and not with a view to distribution of 
this Warrant or the shares of Common Stock issuable upon exercise hereof 
within the meaning of the Act and the rules and regulations thereunder.  

          (b)  The Purchaser realizes that the purchase of this Warrant is a 
speculative investment, and that the economic benefits which may be derived 
therefrom are uncertain.  In determining whether or not to purchase the 
Warrant, the Purchaser has relied solely upon the 


                                      -5-

<PAGE>

publicly-available materials filed by the Company with the Securities and 
Exchange Commission, copies of which have been reviewed by the Purchaser, and 
upon independent investigations made by the Purchaser and its representatives.

          (c)  The Purchaser represents to the Company that he is an 
"accredited investor" as defined in Rule 501(a) of Regulation D promulgated 
under the Act, by virtue of being (i) a natural person whose individual net 
worth, or joint net worth with his spouse, at the time of the purchase 
exceeds $1,000,000 or (ii) a natural person who had an individual income in 
excess of $200,000 in each of the two most recent years or joint income with 
his spouse in excess of $300,000 in each of those years and has a reasonable 
expectation of reaching the same income level in the current year.

          (d)  The holder of this Warrant, by acceptance hereof, agrees to 
give written notice to the Company before exercising or transferring this 
Warrant, in whole or in part, or transferring any shares of Common Stock 
issuable or issued upon the exercise hereof, of such holder's intention to do 
so, describing briefly the manner of any proposed exercise or transfer.  Such 
holder shall also provide the Company with an opinion of counsel satisfactory 
to the Company to the effect that the proposed exercise or transfer of this 
Warrant or transfer of shares may be effected without registration or 
qualification under the Act and any applicable state securities laws of this 
Warrant and the shares of Common Stock issuable or issued upon the exercise 
hereof.  Upon receipt of such written notice and opinion by the Company, such 
holder shall be entitled to exercise this Warrant in accordance with its 
terms, or to transfer this Warrant, or to transfer shares of Common Stock 
issuable or issued upon the exercise of this Warrant, all in accordance with 
the terms of the notice delivered by such holder to the Company, provided 
that an appropriate legend respecting the aforesaid restrictions on transfer 
may be endorsed on this Warrant or the certificates for such shares.  In the 
event of a proposed transfer of this Warrant, prior to the transfer the 
proposed transferee shall execute and deliver to the Company a warrant 
transfer letter in the form attached hereto.  

          8.   Subject to the provisions of paragraph 7 hereof, this Warrant 
and all rights hereunder are transferable, in whole or in part, at the 
principal office of the Company by the holder hereof in person or by duly 
authorized attorney, upon surrender of this Warrant properly endorsed.  Each 
taker and holder of this Warrant, by taking or holding the same, consents and 
agrees that the bearer of this Warrant, when endorsed, may be treated by the 
Company and all other persons dealing with this Warrant as the absolute owner 
hereof for any purpose and as the person entitled to exercise the rights 
represented by this Warrant, or to the transfer hereof on the books of the 
Company, any notice to the contrary notwithstanding; but until such transfer 
on such books, the Company may treat the registered holder hereof as the 
owner for all purposes.

          9.   This Warrant is exchangeable, upon the surrender hereof by the 
holder hereof at the principal office of the Company, for new Warrants of 
like tenor representing in the aggregate the right to subscribe for and 
purchase the number of shares which may be subscribed for and purchased 
hereunder, each of such new Warrants to represent the right to 


                                      -6-

<PAGE>

subscribe for and purchase such number of shares as shall be designated by 
said holder hereof at the time of such surrender.

          10.  All questions concerning this Warrant will be governed and 
interpreted and enforced in accordance with the internal law of the State of 
Minnesota.

          IN WITNESS WHEREOF, the Company has caused this Warrant to be 
signed by its duly authorized officer and this Warrant to be dated as of 
March 9, 1999.

                                         GALAGEN INC.

                                         By
                                           -----------------------------------

                                         Its
                                            ----------------------------------


                           RESTRICTION ON TRANSFER

          The securities evidenced hereby may not be transferred without (i) 
the opinion of counsel satisfactory to the Company that such transfer may be 
lawfully made without registration under the Securities Act of 1933, as 
amended, and all applicable state securities laws or (ii) such registration.


                                      -7-

<PAGE>

                                  ASSIGNMENT
                                          
                     (To Be Signed Only Upon Assignment)


          FOR VALUE RECEIVED, the undersigned hereby sells, assigns and

transfers unto ___________________________________________________________ this

Warrant, and appoints ____________________________________________________ to

transfer this Warrant on the books of GalaGen Inc. with the full power of

substitution in the premises.


Dated:  
      -------------------------------------

In the presence of:  
                   -------------------------------------


                                             
                                             -----------------------------------
                                             (Signature must conform in all
                                             respects to the name of the holder
                                             as specified on the face of this
                                             Warrant without any alteration or
                                             change whatsoever, and the
                                             signature must be guaranteed in the
                                             usual manner)

<PAGE>

                       FORM OF WARRANT TRANSFER LETTER


To:  GalaGen Inc. 


Ladies and Gentlemen:

     The undersigned is a proposed transferee of the warrant (the "Warrant") 
to purchase ____________________ shares of Common Stock, par value $.01 
("Common Stock"), of GalaGen Inc., a Delaware corporation (the "Company"), 
currently registered in the name of ____________________.  In order to induce 
the Company to consent to the transfer of the Warrant, the undersigned hereby 
represents, warrants and agrees as follows:

     1.   The undersigned acknowledges that neither the Warrant nor any of 
the shares of Common Stock issuable upon exercise thereof have been 
registered under the Securities Act of 1933, as amended (the "Act"), or any 
state securities laws and that, accordingly, the Warrant and such shares of 
Common Stock may only be transferred in accordance with the terms of 
paragraph 7 of the Warrant.  

     2.   The undersigned is acquiring the Warrant for investment and not 
with a view to distribution of the Warrant or the shares of Common Stock 
issuable upon exercise thereof within the meaning of the Act and the rules 
and regulations thereunder.

     3.   The undersigned is an "accredited investor" as defined in Rule 
501(a) of Regulation D promulgated under the Act.  

                              Signature 

---------------------------------------

                              Address 
                                      ----------------------------------------

                              Date 
                                   -------------------------------------------

<PAGE>

                           FORM OF EXERCISE NOTICE
                                          
            To be Executed by the Holder of this Warrant if such Holder
                                          
               Desires to Exercise this Warrant in Whole or in Part:

To:  GalaGen Inc. (the "Company")

          The undersigned 
                         --------------------------------------------
                       Please insert Social Security or other
                          identifying number of Purchaser:
                    
                    -------------------------------------------

hereby irrevocably elects to exercise the right of purchase represented by 
this Warrant for, and to purchase thereunder, ______________________ shares 
of the Common Stock provided for therein and tenders payment herewith to the 
order of the Company in the amount of $______________________, such payment 
being made as provided on the face of this Warrant.

     In order to induce the Company to consent to the exercise of this 
Warrant, the undersigned hereby represents, warrants and agrees as follows:

     1.   The undersigned acknowledges that neither this Warrant nor any of 
the shares of Common Stock issuable upon exercise hereof have been registered 
under the Securities Act of 1933, as amended (the "Act"), or any state 
securities laws and that, accordingly, this Warrant may be exercised and the 
shares of Common Stock issued pursuant to this exercise may only be 
transferred in accordance with the terms of paragraph 7 of this Warrant.  

     2.   The undersigned is acquiring the shares of Common Stock issued 
pursuant to this exercise for investment and not with a view to distribution 
of such shares within the meaning of the Act and the rules and regulations 
thereunder.

     3.   The undersigned is an "accredited investor" as defined in Rule 
501(a) of Regulation D promulgated under the Act.   

<PAGE>

          The undersigned requests that certificates for such shares of 
Common Stock be issued as follows:

Name:        
             ------------------------------------------------------------------

Address:     
             ------------------------------------------------------------------

Deliver to:  
             ------------------------------------------------------------------

Address:     
             ------------------------------------------------------------------

and, if such number of shares of Common Stock shall not be all the shares of 
Common Stock purchasable hereunder, that a new Warrant for the balance 
remaining of the shares of Common Stock purchasable under this Warrant be 
registered in the name of, and delivered to, the undersigned at the address 
stated below.

Address:     
             ------------------------------------------------------------------


                              Signature 
                                        ---------------------------------------
                                        (Signature must conform in all respects
                                        to the name of the holder as written
                                        specified on the face of this Warrant
                                        without any alteration or change
                                        whatsoever)

Dated:  
      ------------------------