1
THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR INVESTMENT
AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 OR ANY STATE
SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE
OF SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER SAID ACT AND ANY APPLICABLE
STATE SECURITIES LAWS.

THIS WARRANT AND THE SHARES PURCHASABLE HEREUNDER ARE SUBJECT TO RESTRICTIONS ON
TRANSFER CONTAINED IN THAT CERTAIN BIOSTAR, INC. NOTE AND WARRANT PURCHASE
AGREEMENT, DATED MARCH 20, 1996 WHICH RESTRICTIONS ON TRANSFER ARE INCORPORATED
HEREIN BY REFERENCE.


                               WARRANT TO PURCHASE
                            SHARES OF COMMON STOCK OF
                                  BIOSTAR, INC.
                           (VOID AFTER APRIL 15, 2001)

          This certifies that ____________ (the "Holder"), or assigns, for value
received, is entitled to purchase from BioStar, Inc., a Delaware corporation
(the "Company"), having a place of business at 6655 Lookout Road, Boulder,
Colorado 80301, a maximum of ___________ fully paid and nonassessable shares of
the Company's Common Stock ("Common Stock") for cash at a price of Twenty-Three
Cents ($.23) per share (the "Stock Purchase Price") at any time or from time to
time up to and including 5:00 p.m. (Mountain Time) on the earlier of (i) the
fourth anniversary of the closing of the initial public offering of the
Company's Common Stock pursuant to a registration statement under the Securities
Act of 1933, as amended, or (ii) April 15, 2001, such earlier day being referred
to herein as the "Expiration Date," upon surrender to the Company at its
principal office (or at such other location as the Company may advise the Holder
in writing) of this Warrant properly endorsed with the Form of Subscription
attached hereto duly filled in and signed and, if applicable, upon payment in
cash or by check of the aggregate Stock Purchase Price for the number of shares
for which this Warrant is being exercised determined in accordance with the
provisions hereof. The Stock Purchase Price and the number of shares purchasable
hereunder are subject to adjustment as provided in Section 3 of this Warrant.

I.        EXERCISE; ISSUANCE OF CERTIFICATES; PAYMENT FOR SHARES.

          A. GENERAL. This Warrant is exercisable at the option of the holder of
record hereof, at any time or from time to time, up to the Expiration Date for
all or any part of the shares of Common Stock (but not for a fraction of a
share) which may be purchased hereunder.

          B. ISSUANCE OF CERTIFICATES. The Company agrees that the shares of 
Common Stock purchased under this Warrant 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, properly
endorsed, the completed, executed Form of Subscription delivered and payment
made for such shares. Certificates for the shares of Common Stock so purchased,
together with any other securities or property to which the Holder hereof is
entitled 



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upon such exercise, shall be delivered to the Holder hereof by the Company at
the Company's expense within a reasonable time after the rights represented by
this Warrant have been so exercised. In case of a purchase of less than all the
shares which may be purchased under this Warrant, the Company shall cancel this
Warrant and execute and deliver a new Warrant or Warrants of like tenor for the
balance of the shares purchasable under the Warrant surrendered upon such
purchase to the Holder hereof within a reasonable time. Each stock certificate
so delivered shall be in such denominations of Common Stock as may be requested
by the Holder hereof and shall be registered in the name of such Holder.

          C. NET ISSUE EXERCISE. Notwithstanding any provisions herein to the 
contrary, if the fair market value of one share of the Company's Common Stock is
greater than the Stock Purchase Price (at the date of calculation as set forth
below), in lieu of exercising this Warrant for cash, the Holder may elect to
receive shares equal to the value (as determined below) of this Warrant (or the
portion thereof being canceled) by surrender of this Warrant at the principal
office of the Company together with the properly endorsed Form of Subscription
and notice of such election in which event the Company shall issue to the Holder
a number of shares of Common Stock computed using the following formula:

            X = Y (A-B)
                -------
                  A

Where       X =   the number of shares of Common Stock to be issued to the 
                  Holder

            Y =   the number of shares of Common Stock purchasable under 
                  the Warrant or, if only a portion of the Warrant is being 
                  exercised, the portion of the Warrant being canceled (at the 
                  date of such calculation)

            A =   the fair market value of one share of the Company's Common 
                  Stock (at the date of such calculation)

            B =   Stock Purchase Price (as adjusted to the date of such
                  calculation)

For purposes of the above calculation, fair market value of one share of Common
Stock shall be determined by the Company's Board of Directors in good faith;
provided, however, that where there exists a public market for the Company's
Common Stock at the time of such exercise, the fair market value per share shall
be the average of the closing bid and asked prices of the Common stock quoted in
the Over-The-Counter Market Summary or the last reported sale price of the
Common Stock or the closing price quoted on the Nasdaq National Market or on any
exchange on which the Common Stock is listed, whichever is applicable, as
published in the Western Edition of The Wall Street Journal for the five (5)
trading days prior to the date of determination of fair market value.

I.        SHARES TO BE FULLY PAID; RESERVATION OF SHARES. The Company covenants 
and agrees that all shares of Common Stock which may be issued upon the exercise
of the rights represented by this Warrant will, upon issuance, be duly
authorized, validly issued, fully paid and nonassessable and free from all
preemptive rights of any stockholder and free of all taxes, liens 




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and charges with respect to the issue thereof. The Company further covenants and
agrees that, except as noted in the last two sentences of the introductory
paragraph of this Warrant, during the period within which the rights represented
by this Warrant may be 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
authorized but unissued Common Stock, or other securities and property, when and
as required to provide for the exercise of the rights represented by this
Warrant. The Company will take all such action as may be necessary to assure
that such shares of Common Stock may be issued as provided herein without
violation of any applicable law or regulation, or of any requirements of any
domestic securities exchange upon which the Common Stock may be listed;
provided, however, that the Company shall not be required to effect a
registration under federal or state securities laws with respect to such
exercise. The Company will not take any action which would result in any
adjustment of the Stock Purchase Price (i) if the total number of shares of
Common Stock issuable after such action upon exercise of all outstanding
warrants, together with all shares of Common Stock then outstanding and all
shares of Common Stock then issuable upon exercise of all options and upon the
conversion of all convertible securities then outstanding, would exceed the
total number of shares of Common Stock then authorized by the Company's
Certificate of Incorporation, or (ii) if the total number of shares of Common
Stock issuable after such action upon the conversion of all such shares of
Preferred Stock, together with all shares of Common Stock then issuable upon
exercise of all options and upon the conversion of all such shares of Preferred
Stock, together with all shares of Common Stock then outstanding and all shares
of Common Stock then issuable upon exercise of all options and upon the
conversion of all convertible securities then outstanding would exceed the total
number of shares of Common Stock then authorized by the Company's Certificate of
Incorporation.

II.       ADJUSTMENT OF STOCK PURCHASE PRICE AND NUMBER OF SHARES. The Stock 
Purchase Price and the number of shares purchasable upon the exercise of this
Warrant shall be subject to adjustment from time to time upon the occurrence of
certain events described in this Section 3. Upon each adjustment of the Stock
Purchase Price, the Holder of this Warrant shall thereafter be entitled to
purchase, at the Stock Purchase Price resulting from such adjustment, the number
of shares obtained by multiplying the Stock 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
Stock Purchase Price resulting from such adjustment.

          A.   SUBDIVISION OF COMBINATION OF STOCK. In case the Company shall at
any time subdivide its outstanding shares of Common Stock into a greater number
of shares, the Stock 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
smaller number of shares, the Stock Purchase Price in effect immediately prior
to such combination shall be proportionately increased.

          B.   DIVIDENDS IN COMMON STOCK, OTHER STOCK, PROPERTY,
RECLASSIFICATION. If at any time or from time to time the Holders of Common
Stock (or any shares of stock or other 



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securities at the time receivable upon the exercise of this Warrant) shall have
received or become entitled to receive, without payment therefor,

               1. Common Stock or any shares of stock or other securities which 
are at any time directly or indirectly convertible into or exchangeable for
Common Stock, or any rights or options to subscribe for, purchase or otherwise
acquire any of the foregoing by way of dividend or other distribution;

               2. Any cash paid or payable otherwise than as a cash dividend; or

               3. Common Stock or additional stock or other securities or 
property (including cash) by way of spin-off, split-up, reclassification,
combination of shares or similar corporate rearrangement (other than (i) shares
of Common Stock issued as a stock split, adjustments in respect of which shall
be covered by the terms of Section 3.1 above or (ii) an event for which
adjustment is otherwise made pursuant to Section 3.3 below), then and in each
such case, the Holder hereof shall, upon the exercise of this Warrant, be
entitled to receive, in addition to the number of shares of Common Stock
receivable thereupon, and without payment of any additional consideration
therefor, the amount of stock and other securities and property (including cash
in the cases referred to in clauses 3.2.1 and 3.2.2 above) which such Holder
would hold on the date of such exercise had he been the holder of record of such
Common Stock as of the date on which holders of Common Stock received or became
entitled to receive such shares or all other additional stock and other
securities and property.

          C.   REORGANIZATION, RECLASSIFICATION, CONSOLIDATION, MERGER OR SALE.
If any capital reorganization of the capital stock of the Company, or any
consolidation or merger of the Company with another corporation, or the sale of
all or substantially all of its assets to another corporation shall be effected
in such a way that holders of Common Stock shall be entitled to receive stock,
securities, or other assets or property, then, as a condition of such
reorganization, reclassification, consolidation, merger or sale, lawful and
adequate provisions shall be made whereby the Holder hereof shall thereafter
have the right to purchase and receive (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
other assets or property as may be issued or payable with respect to or in
exchange for a number of outstanding shares of such Common Stock equal to the
number of shares of such stock immediately theretofore purchasable and
receivable upon the exercise of the rights represented hereby; provided,
however, that in the event the value of the stock, securities or other assets or
property (determined in good faith by the Board of Directors of the Company)
issuable or payable with respect to one share of the Common Stock of the Company
immediately theretofore purchasable and receivable upon the exercise of the
rights represented hereby is in excess of the Stock Purchase Price hereof
effective at the time of the merger and securities received in such
reorganization, if any, are publicly traded, then this Warrant shall expire
unless exercised prior to the reorganization. In any reorganization described
above, appropriate provision shall be made with respect to the rights and
interests of the Holder of this Warrant to the end that the provisions hereof
(including, without limitation, provisions for adjustments of the Stock Purchase
Price and of the number of shares purchasable and receivable upon the exercise
of this Warrant) shall



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thereafter be applicable, as nearly as may be, in relation to any shares of
stock, securities or assets thereafter deliverable upon the exercise hereof. The
Company will not effect any such consolidation, merger or sale unless, prior to
the consummation thereof, the successor corporation (if other than the Company)
resulting from such consolidation or the corporation purchasing such assets
shall assume by written instrument, executed and mailed or delivered 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.

          D.   NOTICE OF ADJUSTMENT. Upon any adjustment of the Stock Purchase 
Price or any increase or decrease in the number of shares purchasable upon the
exercise of this Warrant, 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. The
notice shall be signed by the Company's chief financial officer and shall state
the Stock Purchase Price resulting from 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.

          E.   OTHER NOTICES.  If at any time: 

               1. the Company shall declare any cash dividend upon its Common 
                  Stock;
                  
               2. the Company shall declare any dividend upon its Common Stock
                  payable in stock or make any special dividend or other
                  distribution to the holders of its Common Stock;
                  
               3. 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;
                  
               4. there shall be a voluntary or involuntary dissolution, 
                  liquidation or winding-up of the Company; or
                  
               5. there shall be an initial public offering of Company 
                  securities;

then, in any one or more of said cases, the Company shall give, by first class
mail, postage prepaid, addressed to the Holder of this Warrant at the address of
such Holder as shown on the books of the Company, (a) at least ten (10) days
prior written notice of the date on which the books of the Company shall close
or a record shall be taken for such dividend, distribution or subscription
rights or for determining rights to vote in respect of any such reorganization,
reclassification, consolidation, merger, sale, dissolution, liquidation or
winding-up, and (b) in the case of any such reorganization, reclassification,
consolidation, merger, sale, dissolution, liquidation, winding-up or public
offering, at least ten (10) days prior written notice of the date when the same
shall take place; provided, however, that the Holder shall make a best efforts
attempt to respond to such notice as early as possible after the receipt
thereof. Any notice given in accordance with the foregoing clause (a) shall also
specify, in the case of any such dividend, 



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distribution or subscription rights, the date on which the holders of Common
Stock shall be entitled thereto. Any notice given in accordance with the
foregoing clause (b) shall also specify the date on which the holders of Common
Stock shall be entitled to exchange their Common Stock for securities or other
property deliverable upon such reorganization, reclassification, consolidation,
merger, sale, dissolution, liquidation, winding-up or public offering, as the
case may be.

          F.   CERTAIN EVENTS. If any change in the outstanding Common Stock of 
the Company or any other event occurs as to which the other provision of this
Section 3 are not strictly applicable or if strictly applicable would not fairly
protect the purchase rights of the Holder of the Warrant in accordance with such
provisions, the Board of Directors of the Company shall make an adjustment in
the number and class of shares available under the Warrant, the Stock Purchase
Price or the application of such provisions, so as to protect such purchase
rights as aforesaid. The adjustment shall be such as will give the Holder of the
Warrant upon exercise for the same aggregate Stock Purchase Price the total
number, class and kind of shares as he would have owned had the Warrant been
exercised prior to the event and had he continued to hold such shares until
after the event requiring adjustment.

III.      ISSUE TAX. The issuance of certificates for shares of Common Stock 
upon the exercise of the Warrant shall be made without charge to the Holder of
the Warrant for any issue tax (other than any applicable income taxes) in
respect thereof; provided, however, that the Company shall not be required to
pay any tax which may be payable in respect of any transfer involved in the
issuance and delivery of any certificate in a name other than that of the then
Holder of the Warrant being exercised.

IV.       CLOSING OF BOOKS. The Company will at no time close its transfer books
against the transfer of any warrant or of any shares of Common Stock issued or
issuable upon the exercise of any warrant in any manner which interferes with
the timely exercise of this Warrant.

V.        NO VOTING OR DIVIDEND RIGHTS; LIMITATION OF LIABILITY. Nothing 
contained in this Warrant shall be construed as conferring upon the holder
hereof the right to vote or to consent or to receive notice as a stockholder of
the Company or any other matters or any rights whatsoever as a stockholder of
the Company. No dividends or interest shall be payable or accrued in respect of
this Warrant or the interest represented hereby or the shares purchasable
hereunder until, and only to the extent that, this Warrant shall have been
exercised. No provision hereof in the absence of affirmative action by the
holder to purchase shares of Common Stock, and no mere enumeration herein of the
rights or privileges of the holder hereof, shall give rise to any liability of
such holder for the Stock Purchase Price or as a stockholder of the Company,
whether such liability is asserted by the Company or by its creditors.

VI.       REGISTRATION RIGHTS AGREEMENT. The registration rights of the Holder
(including Holders' successors) with respect to this Warrant and the underlying
stock will be the same as granted to the holders of the Company's Preferred
Stock.

VII.      WARRANTS TRANSFERABLE. Subject to compliance with applicable federal
and state securities laws and the transfer restrictions set forth in the Note
and Warrant Purchase Agreement 



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dated as of March 20, 1996, under which this Warrant was purchased, this Warrant
and all rights hereunder are transferable, in whole or in part, without charge
to the holder hereof (except for transfer taxes), upon surrender of this Warrant
properly endorsed and in compliance with the provisions of the Note and Warrant
Purchase Agreement. Each taker and holder of this Warrant, by taking or holding
the same, consents and agrees that this Warrant, when endorsed in blank, shall
be deemed negotiable, and that the holder hereof, when this Warrant shall have
been so endorsed, may be treated by the Company, at the Company's option, 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 owner hereof as the owner for all purposes.

VIII.     RIGHTS AND OBLIGATIONS SURVIVE EXERCISE OF WARRANT. The rights and
obligations of the Company, of the holder of this Warrant and of the holder of
shares of Common Stock issued upon exercise of this Warrant, referred to in
Sections 7 and 8 shall survive the exercise of this Warrant.

IX.       MODIFICATION AND WAIVER. This Warrant and any provision hereof may be
changed, waived, discharged or terminated only by an instrument in writing
signed by the party against which enforcement of the same is sought, provided
that any change, waiver, discharge or termination agreed to in writing by a
majority in interest of holders of warrants of the Company of even date issued
pursuant to the Note and Warrant Purchase Agreement shall be binding on Holder
and assigns.

X.        NOTICES. Any notice, request or other document required or permitted 
to be given or delivered to the older hereof or the Company shall be delivered
or shall be sent by certified mail, postage prepaid, to each such holder at its
address as shown on the books of the Company or to the Company at the address
indicated therefor in the first paragraph of this Warrant or such other address
as either may from time to time provide to the other.

XI.       BINDING EFFECT ON SUCCESSORS. This Warrant shall be binding upon any
corporation succeeding the Company by merger, consolidation or acquisition of
all or substantially all of the Company's assets. All of the obligations of the
Company relating to the Common Stock issuable upon the exercise of this Warrant
shall survive the exercise and termination of this Warrant. All of the covenants
and agreements of the Company shall inure to the benefit of the successors and
assigns of the holder hereof.

XII.      DESCRIPTIVE HEADINGS AND GOVERNING LAW. The description headings of 
the several sections and paragraphs of this Warrant are inserted for convenience
only and do not constitute a part of this Warrant. This Warrant shall be
construed and enforced in accordance with, and the rights of the parties shall
be governed by, the laws of the State of Colorado.

XIII.     LOST WARRANTS. The Company represents and warrants to the Holder 
hereof that upon receipt of evidence reasonably satisfactory to the Company of
the loss, theft, destruction, or mutilation of this Warrant and, in the case of
any such loss, theft or destruction, upon receipt of an indemnity reasonably
satisfactory to the Company, or in the case of any such mutilation upon




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surrender and cancellation of such Warrant, the Company, at its expense, will
make and deliver a new Warrant, of like tenor, in lieu of the lost, stolen,
destroyed or mutilated Warrant.

XIV.     FRACTIONAL SHARES. No fractional shares shall be issued upon exercise 
of this Warrant. The Company shall, in lieu of issuing any fractional share, pay
the holder entitled to such fraction a sum in cash equal to such fraction
multiplied by the then effective Stock Purchase Price.

         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed by its officers, thereunto duly authorized this _____, day of April,
1996.

                                  BIOSTAR, INC.
                                  a Delaware corporation



                                  --------------------------------------
                                  Teresa W. Ayers
                                  President and Chief Operating Officers
                                  




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                                    EXHIBIT A


                                SUBSCRIPTION FORM



                                                      Date:______________, 19___




BioStar, Inc.
6655 Lookout Road
Boulder, Colorado  80301

Gentlemen:


[ ]      The undersigned hereby elects to exercise the warrant issued to it by
         BioStar, Inc. (the "Company") and dated March _____, 1996, Warrant No.
         CW-___ (the "Warrant") and to purchase thereunder __________ shares of
         the Common Stock of the Company (the "Shares") at a purchase price of
         ______________________________ ($______) per Share, or an aggregate
         purchase price of ______________________________ ($______) (the
         "Purchase Price").

[ ]      The undersigned hereby elects to convert ___________________ percent
         (___%) of the value of the Warrant pursuant to the provisions of
         Section 2 of the Warrant.

         Pursuant to the terms of the Warrant the undersigned has delivered the
Purchase Price herewith in full in cash or by certified check or wire transfer.


                                       Very truly yours,



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

                                       By:
                                          --------------------------------------

                                       Title:
                                             -----------------------------------



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