Document:

<PAGE>
                                   Exhibit 4.3

                     Warrant to Wharton Capital Partners, Ltd.

THIS COMMON STOCK PURCHASE WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"). THE HOLDER HEREOF, BY PURCHASING
THIS COMMON STOCK PURCHASE WARRANT, AGREES FOR THE BENEFIT OF THE COMPANY THAT
SUCH SECURITIES MAY BE OFFERED, SOLD OR OTHERWISE TRANSFERRED ONLY (A) TO THE
COMPANY, (B) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT, OR (C) IF REGISTERED UNDER THE SECURITIES ACT AND ANY APPLICABLE STATE
SECURITIES LAWS.

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

                             BOSTON BIOMEDICA, INC.

                          COMMON STOCK PURCHASE WARRANT

--------------------------------------------------------------------------------
                                  No. 2
Number of shares: 10,000          Holder:    Wharton Capital Partners, Ltd.
Expiration Date:  August 25, 2005            545 Madison Avenue
                                             New York, New York 10022
Purchase Price Per Share:  $3.60

          For identification only. The governing terms of this Warrant
                              are set forth below.
--------------------------------------------------------------------------------

Boston Biomedica, Inc., a Massachusetts corporation (the "COMPANY"), hereby
certifies that, for value received, Wharton Capital Partners, Ltd. or its
assigns (the "HOLDER"), is entitled, subject to the terms set forth below, to
purchase from the Company at any time or from time to time after the date
hereof and prior to the fifth anniversary hereof (the "EXERCISE PERIOD"), at
the Purchase Price hereinafter set forth, Ten Thousand (10,000) shares of the
fully paid and nonassessable shares of common stock of the Company, $0.01 par
value per share (the "Common Stock"). The number and character of such shares
of Common Stock and the Purchase Price are subject to adjustment as provided
herein.

         The purchase price per share of Common Stock issuable upon exercise of
this Warrant (the "PURCHASE PRICE") shall initially be equal to 120% of the
average Closing Bid Price as published by Bloomberg, L.P. of the Common Stock on
the day immediately preceding the date hereof; PROVIDED, HOWEVER, that the
Purchase Price shall be adjusted from time to time as provided herein.

         Capitalized terms used herein not otherwise defined shall have the
meanings ascribed thereto in that certain Securities Purchase Agreement of even
date herewith between the Company and GCA Strategic Investment Fund Limited (the
"Purchase Agreement"). By execution of this Warrant, the Holder hereof agrees to
be bound by and to benefit from the provisions of the Purchase Agreement

                                       1
<PAGE>

set forth herein. As used herein the following terms, unless the context
otherwise requires, have the following respective meanings:

                  (a) The term "COMPANY" shall include Boston Biomedica, Inc.
         and any corporation that shall succeed or assume the obligations of
         such corporation hereunder.

                  (b) The term "COMMON STOCK" includes (a) the Company's common
         stock, par value $0.01 per share, (b) any other capital stock of any
         class or classes (however designated) of the Company, authorized on or
         after the date hereof, the Holders of which shall have the right,
         without limitation as to amount, either to all or to a share of the
         balance of current dividends and liquidating dividends after the
         payment of dividends and distributions on any shares entitled to
         preference, and the Holders of which shall ordinarily, in the absence
         of contingencies, be entitled to vote for the election of a majority of
         directors of the Company (even though the right so to vote has been
         suspended by the happening of such a contingency) and (c) any other
         securities into which or for which any of the securities described in
         (a) or (b) may be converted or exchanged pursuant to a plan of
         recapitalization, reorganization, merger, sale of assets or otherwise.

                  (c) The term "OTHER SECURITIES" refers to any stock (other
         than Common Stock) and other securities of the Company or any other
         person (corporate or otherwise) that the Holder of this Warrant at any
         time shall be entitled to receive, or shall have received, on the
         exercise of this Warrant, in lieu of or in addition to Common Stock, or
         that at any time shall be issuable or shall have been issued in
         exchange for or in replacement of Common Stock or Other Securities
         pursuant to Section 4 or otherwise.

         1.       EXERCISE OF WARRANT.

                  1.1      METHOD OF EXERCISE.

                  (a) This Warrant may be exercised in whole or in part (but not
         as to a fractional share of Common Stock), at any time and from time to
         time during the Exercise Period by the Holder hereof by delivery of a
         notice of exercise (a "NOTICE OF EXERCISE") substantially in the form
         attached hereto as EXHIBIT A via facsimile to the Company. Prior to
         sending the Notice of Exercise via facsimile, the Holder shall give
         Richard Schumacher notice of its intent to submit a Notice of Exercise
         by telephone (and if Mr. Schumacher is not available to be reached by
         telephone, either Kevin Quinlan or Kathi Benjamin by telephone, or such
         other person designated by the Company after the Closing Date).
         Promptly thereafter the Holder shall surrender this Warrant (if the
         entire amount of the Warrant is subject to the Notice of Exercise) to
         the Company at its principal office via overnight delivery service,
         accompanied by payment of the Purchase Price multiplied by the number
         of shares of Common Stock for which this Warrant is being exercised
         (the "EXERCISE PRICE"). Payment of the Exercise Price shall be made, at
         the option of the Holder, (i) by check or bank draft payable to the
         order of the Company, or (ii) by wire transfer to the account of the
         Company. Upon exercise, the Holder shall be entitled to receive within
         three Trading Days of the Exercise Date (as defined herein), one or
         more certificates, issued in the Holder's name or

                                       2
<PAGE>

         in such name or names as the Holder may direct, subject to the
         limitations on transfer contained herein, for the number of shares of
         Common Stock so purchased. The shares of Common Stock so purchased
         shall be deemed to be issued as of the close of business on the date on
         which the Company shall have received from the Holder payment in full
         of the Exercise Price (the "EXERCISE DATE").

                  (b) Upon exercise of a portion of this Warrant in accordance
         with the terms hereof, records showing the amount so exercised and the
         date of exercise shall be maintained on a ledger substantially in the
         form of ANNEX B attached hereto (an originally signed and executed copy
         of which shall be delivered to the Company with each Notice of
         Exercise). The Company shall maintain the originally signed and
         executed ledger and the Holder shall maintain a copy thereof. Upon
         execution of the exercise of the Warrants contemplated by the Notice of
         Exercise, the Company shall deliver to the Holder a copy of ANNEX B
         signed and executed by the Company, and the Holder shall deliver to the
         Company a copy of Annex B signed by the Holder. It is specifically
         contemplated that the Company shall act as the calculation agent for
         all exercises of this Warrant. The Holder and any assignee, by
         acceptance of this Warrant, acknowledges and agrees that, by reason of
         the provisions of this paragraph, following an exercise of a portion of
         this Warrant, the number of shares of Common Stock represented by this
         Warrant will be the amount indicated on ANNEX B attached hereto (which
         may be less than the amount stated on the face hereof).

                  (c) In the event there is a dispute as to the number of shares
         of Common Stock the Holder is entitled to receive upon exercise of this
         Warrant, the Company shall issue to the Holder the number of shares not
         in dispute and the Company and the Holder will use their best efforts
         to resolve such dispute within one Business Day following the receipt
         of a Notice of Exercise. If such dispute cannot be resolved within such
         one-day period, the Company and the Holder shall submit the dispute to
         an independent accountant mutually agreed upon by the Company and the
         Holder to make a final and binding determination of the number of
         shares owed to the Holder. The Company shall issue shares of Common
         Stock owed to Holder as a result of the resolution of the dispute
         within two Business Days following the receipt of the accountant's
         independent determination.

                  1.2 REGULATION D RESTRICTIONS. The Holder hereof represents
and warrants to the Company that it has acquired this Warrant and anticipates
acquiring the shares of Common Stock issuable upon exercise of the Warrant
solely for its own account for investment purposes and not with a view to or for
resale of such securities unless such resale has been registered with the
Commission or an applicable exemption is available therefor and provided that
the Holder shall have furnished to the Company an opinion of counsel in form and
substance reasonably satisfactory to the Company, to the effect that such
transfer is exempt from the registration requirements of the Securities Act and
any applicable state securities laws.

                  1.3 COMPANY ACKNOWLEDGMENT. The Company will, at the time of
the exercise of this Warrant, upon request of the Holder hereof, acknowledge in
writing its continuing obligation to afford to such Holder the registration
rights to which such Holder shall continue to be entitled

                                       3
<PAGE>

after such exercise in accordance with the provisions of a Registration Rights
Agreement dated the date hereof (the "Registration Rights Agreement").

                  1.4 LIMITATION ON EXERCISE. Notwithstanding the rights of the
Holder to exercise all or a portion of this Warrant as described herein, such
exercise rights shall be limited, solely to the extent set forth in the Purchase
Agreement as if such provisions were specifically set forth herein. In addition,
the number of shares of Common Stock issuable upon exercise of this Warrant is
subject to reduction as specified in Section 10.3 of the Purchase Agreement.

         2. DELIVERY OF STOCK CERTIFICATES, ETC., ON EXERCISE. As soon as
practicable after the exercise of this Warrant, and in any event within three
(3) Business Days thereafter, the Company at its expense (including the payment
by it of any applicable issue, stamp or transfer taxes) will cause to be issued
in the name of and delivered to the Holder thereof, or, to the extent
permissible hereunder, to such other person as such Holder may direct, a
certificate or certificates for the number of fully paid and nonassessable
shares of Common Stock (or Other Securities) to which such Holder shall be
entitled on such exercise, plus, in lieu of any fractional share to which such
Holder would otherwise be entitled, cash equal to such fraction multiplied by
the then applicable Purchase Price, together with any other stock or other
securities and property (including cash, where applicable) to which such Holder
is entitled upon such exercise pursuant to Section 1 or otherwise.

         3. ADJUSTMENT FOR EXTRAORDINARY EVENTS. The Purchase Price to be paid
by the Holder upon exercise of this Warrant, and the consideration to be
received upon exercise of this Warrant, shall be adjusted in case at any time or
from time to time pursuant to Article 11 of the Purchase Agreement as if such
provisions were specifically set forth herein.

         4. NO IMPAIRMENT. The Company will not, by amendment of its Certificate
of Incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms of this Warrant, but will at all times in good faith assist in the
carrying out of all such terms and in the taking of all such action as may be
necessary or appropriate in order to protect the rights of the Holder of this
Warrant against impairment. Without limiting the generality of the foregoing,
the Company (a) will not increase the par value of any shares of stock
receivable on the exercise of this Warrant above the amount payable therefor on
such exercise, (b) will take all such action as may be necessary or appropriate
in order that the Company may validly and legally issue fully paid and
unassessable shares of stock on the exercise of this Warrant, and (c) will not
transfer all or substantially all of its properties and assets to any other
person (corporate or otherwise), or consolidate with or merge into any other
person or permit any such person to consolidate with or merge into the Company
(if the Company is not the surviving person), unless such other person shall
expressly assume in writing and will be bound by all the terms of this Warrant.

         5. CERTIFICATE AS TO ADJUSTMENTS. In each case of any adjustment or
readjustment in the shares of Common Stock (or Other Securities) issuable on the
exercise of this Warrant, the Company will promptly cause its principal
financial officer to compute such adjustment or readjustment in accordance with
the terms of this Warrant and prepare a certificate setting forth such
adjustment or

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<PAGE>

readjustment and showing in detail the facts upon which such adjustment or
readjustment is based, including a statement of (a) the consideration received
or receivable by the Company for any additional shares of Common Stock (or Other
Securities) issued or sold or deemed to have been issued or sold, (b) the number
of shares of Common Stock (or Other Securities) outstanding or deemed to be
outstanding, and (c) the Purchase Price and the number of shares of Common Stock
to be received upon exercise of this Warrant, in effect immediately prior to
such issue or sale and as adjusted and readjusted as provided in this Warrant.
The Company will forthwith mail a copy of each such certificate to the Holder of
this Warrant, and will, on the written request at any time of the Holder of this
Warrant, furnish to such Holder a like certificate setting forth the Purchase
Price at the time in effect and showing how it was calculated.

         6.       NOTICES OF RECORD DATE, ETC.

                  In the event of

                           (a) any taking by the Company of a record of the
         Holders of any class of securities for the purpose of determining the
         Holders thereof who are entitled to receive any dividend or other
         distribution, or any right to subscribe for, purchase or otherwise
         acquire any shares of stock of any class or any other securities or
         property, or to receive any other right, or

                           (b) any capital reorganization of the Company, any
         reclassification or recapitalization of the capital stock of the
         Company or any transfer of all or substantially all the assets of the
         Company to or consolidation or merger of the Company with or into any
         other Person, or

                           (c) any voluntary or involuntary dissolution,
         liquidation  or winding-up of the Company,

then and in each such event the Company will mail or cause to be mailed to the
Holder of this Warrant a notice specifying (i) the date on which any such record
is to be taken for the purpose of such dividend, distribution or right, and
stating the amount and character of such dividend, distribution or right, and
(ii) the date on which any such reorganization, reclassification,
recapitalization, transfer, consolidation, merger, dissolution, liquidation or
winding-up is to take place, and the time, if any, as of which the Holders of
record of Common Stock (or Other Securities) shall be entitled to exchange their
shares of Common Stock (or Other Securities) for securities or other property
deliverable on such reorganization, reclassification, recapitalization,
transfer, consolidation, merger, dissolution, liquidation or winding-up. Such
notice shall be mailed at least 20 days prior to the date specified in such
notice on which any action is to be taken.

         7. RESERVATION OF STOCK, ETC. ISSUABLE ON EXERCISE OF WARRANT. The
Company will at all times reserve and keep available, solely for issuance and
delivery on the exercise of this Warrant, all shares of Common Stock (or Other
Securities) from time to time issuable on the exercise of this Warrant.

                                       5
<PAGE>

         8. EXCHANGE OF WARRANT. On surrender for exchange of this Warrant,
properly endorsed and in compliance with the restrictions on transfer set forth
in the legend on the face of this Warrant, to the Company, the Company at its
expense will issue and deliver to or on the order of the Holder thereof a new
Warrant of like tenor, in the name of such Holder or as such Holder (on payment
by such Holder of any applicable transfer taxes) may direct, calling in the
aggregate on the face or faces thereof for the number of shares of Common Stock
called for on the face of the Warrant so surrendered or for such lesser number
of shares of Common Stock as may be reflected on the Warrant Exercise Ledger
attached as Annex B.

         9. REPLACEMENT OF WARRANT. On 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 of this
Warrant, on delivery of an indemnity agreement or security reasonably
satisfactory in form and amount to the Company or, in the case of any such
mutilation, on surrender and cancellation of this Warrant, the Company at its
expense will execute and deliver, in lieu thereof, a new Warrant of like tenor.

         10. REMEDIES. The Company stipulates that the remedies at law of the
Holder of this Warrant in the event of any default or threatened default by the
Company in the performance of or compliance with any of the terms of this
Warrant are not and will not be adequate, and that such terms may be
specifically enforced by a decree for the specific performance of any agreement
contained herein or by an injunction against a violation of any of the terms
hereof or otherwise.

         11. NEGOTIABILITY, ETC.. This Warrant is issued upon the following
terms, to all of which each Holder or owner hereof by the taking hereof consents
and agrees:

                   (a) until this Warrant is transferred on the books of the
Company, the Company may treat the registered Holder hereof as the absolute
owner hereof for all purposes, notwithstanding any notice to the contrary; and

                  (b) this Warrant may not be sold, transferred or assigned
except pursuant to an effective registration statement under the Securities Act
or pursuant to an applicable exemption therefrom.

         12. REGISTRATION RIGHTS. The Company is obligated to register the
shares of Common Stock issuable upon exercise of this Warrant in accordance with
the terms of the Registration Rights Agreement.

         13. WARRANT REDEMPTION. Upon occurrence of the events described in
Sections 3.4 and 10.4(c) of the Purchase Agreement, the Company, at the request
of Holder, shall redeem all outstanding Warrants that remain unexercised at a
redemption price equal to the greater of (x) an appraised value of the Warrants,
as determined by Black Sholes, on the date they are called for redemption and
(y) the number of Warrants being redeemed multiplied by the excess of (A) the
average Closing Bid Price of the Common Stock for the five trading days
immediately prior to the date that the Warrants are called for redemption over
(B) the exercise price of the Warrants.

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<PAGE>

         14. NOTICES, ETC. All notices and other communications from the Company
to the Holder of this Warrant shall be mailed by first class registered or
certified mail, postage prepaid, at such address as may have been furnished to
the Company in writing by such Holder or, until any such Holder furnishes to the
Company any address, then to, and at the address of, the last Holder of this
Warrant who has so furnished an address to the Company.

         15. MISCELLANEOUS. This Warrant and any term hereof may be changed,
waived, discharged or terminated only by an instrument in writing signed by the
party against which enforcement of such change, waiver, discharge or termination
is sought. This Warrant shall be construed and enforced in accordance with and
governed by the internal laws of the State of Massachusetts. The headings in
this Warrant are for the purposes of reference only, and shall not limit or
otherwise affect any of the terms hereof. The invalidity or unenforceability of
any provision hereof shall in no way affect the validity or enforceability of
any other provision.

                                       7
<PAGE>

DATED as of August 25, 2000.

                                    BOSTON BIOMEDICA, INC.

                                    By: /s/ Kevin W. Quinlan
                                        ---------------------------------------
                                    Name: Kevin W. Quinlan
                                    Title: President

                                       8
<PAGE>

                                    EXHIBIT A

                        FORM OF NOTICE EXERCISE - WARRANT
                    (To be executed only upon exercise of the
                          Warrant in whole or in part)

To ____________________________________________

         The undersigned registered Holder of the accompanying Warrant, hereby
exercises such Warrant or portion thereof for, and purchases thereunder,
__________ (1) shares of Common Stock (as defined in such Warrant) and herewith
makes payment therefor in the amount and manner set forth below, as of the date
written below. The undersigned requests that the certificates for such shares
of Common Stock be issued in the name of, and delivered to, __________________
whose address is __________________.

         The Exercise Price is paid as follows:

         / /  Certified Bank draft payable to the Company in the
              amount of $_____________.
         / /  Wire transfer to the account of the Company in the
              amount of $___________.

         Upon exercise pursuant to this Notice of Exercise, the Holder will be
in compliance with the Limitation on Exercise (as defined in the Securities
Purchase Agreement pursuant to which this Warrant was issued).

         The Holder of the shares of Common Stock received upon exercise of the
Warrant (the "Common Shares"), covenants and agrees that the Common Shares are
being acquired as an investment and not with a view to the distribution thereof
in violation of the Securities Act and that the Common Shares may not be
transferred, sold, assigned, hypothecated or otherwise disposed of, in whole or
in part except as provided in the legend on the first page of this Warrant and
provided that the Holder shall have furnished the Company an opinion of counsel
in form and substance reasonably acceptable to the Company to the effect that
such transfer is exempt from the registration requirements of the Securities Act
and any applicable state securities laws.*

Date:
     --------------------------------     -------------------------------------
                                          (Name must conform to name
                                          of Holder as specified on
                                          the face of the Warrant)
                                          By:
                                             ----------------------------------
                                             Name:
                                                  -----------------------------
                                             Title:
                                                   ----------------------------

                                          Address of Holder:
                                                            -------------------
                                                            -------------------

Date of exercise:
                 ----------------------------
*  If shares of common Stock are to be issued to anyone other than the
   Holder, this covenant and representation must be made by such other
   Person.

----------------------
   (1)Insert the number of shares of Common Stock as to which the
accompanying Warrant is being exercised. In the case of a partial exercise, a
new Warrant or Warrants will be issued and delivered, representing the
unexercised portion of the accompanying Warrant, to the Holder surrendering the
same.

<PAGE>

                                     ANNEX B

                             WARRANT EXERCISE LEDGER

<TABLE>
<CAPTION>
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             ORIGINAL NUMBER OF         WARRANTS          EXERCISE PRICE         NEW BALANCE           ISSUER              HOLDER
 DATE            WARRANTS              EXERCISED              PAID               OF WARRANTS          INITIALS            INITIALS
-----------------------------------------------------------------------------------------------------------------------------------
<S>          <C>                       <C>                <C>                    <C>                  <C>                 <C>

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</TABLE>

BOSTON BIOMEDICA, INC.                           HOLDER:

By:      _______________________                 By: _____________________
Name:    _______________________                 Name:____________________
Title:   _______________________                 Title:___________________<PAGE>
                                   Exhibit 4.4

                         Warrant to DP Securities, Inc.

THIS COMMON STOCK PURCHASE WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"). THE HOLDER HEREOF, BY PURCHASING
THIS COMMON STOCK PURCHASE WARRANT, AGREES FOR THE BENEFIT OF THE COMPANY THAT
SUCH SECURITIES MAY BE OFFERED, SOLD OR OTHERWISE TRANSFERRED ONLY (A) TO THE
COMPANY, (B) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES
ACT, OR (C) IF REGISTERED UNDER THE SECURITIES ACT AND ANY APPLICABLE STATE
SECURITIES LAWS.

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

                             BOSTON BIOMEDICA, INC.

                          COMMON STOCK PURCHASE WARRANT

--------------------------------------------------------------------------------
                                         No. 3
Number of shares: 10,000                 Holder:    DP Securities, Inc.
Expiration Date:  August 25, 2005                   3655 Nobel Drive
                                                    Suite 540
Purchase Price Per Share: $3.60                     San Diego, CA 92122

          For identification only. The governing terms of this Warrant
                              are set forth below.
--------------------------------------------------------------------------------

Boston Biomedica, Inc., a Massachusetts corporation (the "COMPANY"), hereby
certifies that, for value received, DP Securities, Inc. or its assigns (the
"HOLDER"), is entitled, subject to the terms set forth below, to purchase from
the Company at any time or from time to time after the date hereof and prior to
the fifth anniversary hereof (the "EXERCISE PERIOD"), at the Purchase Price
hereinafter set forth, Ten Thousand (10,000) shares of the fully paid and
nonassessable shares of common stock of the Company, $0.01 par value per share
(the "Common Stock"). The number and character of such shares of Common Stock
and the Purchase Price are subject to adjustment as provided herein.

         The purchase price per share of Common Stock issuable upon exercise of
this Warrant (the "PURCHASE PRICE") shall initially be equal to 120% of the
average Closing Bid Price as published by Bloomberg, L.P. of the Common Stock on
the day immediately preceding the date hereof; PROVIDED, HOWEVER, that the
Purchase Price shall be adjusted from time to time as provided herein.

         Capitalized terms used herein not otherwise defined shall have the
meanings ascribed thereto in that certain Securities Purchase Agreement of even
date herewith between the Company and GCA Strategic Investment Fund Limited (the
"Purchase Agreement"). By execution of this Warrant, the Holder hereof agrees to
be bound by and to benefit from the provisions of the Purchase Agreement

                                       1
<PAGE>

set forth herein. As used herein the following terms, unless the context
otherwise requires, have the following respective meanings:

                  (a) The term "COMPANY" shall include Boston Biomedica, Inc.
         and any corporation that shall succeed or assume the obligations of
         such corporation hereunder.

                  (b) The term "COMMON STOCK" includes (a) the Company's common
         stock, par value $0.01 per share, (b) any other capital stock of any
         class or classes (however designated) of the Company, authorized on or
         after the date hereof, the Holders of which shall have the right,
         without limitation as to amount, either to all or to a share of the
         balance of current dividends and liquidating dividends after the
         payment of dividends and distributions on any shares entitled to
         preference, and the Holders of which shall ordinarily, in the absence
         of contingencies, be entitled to vote for the election of a majority of
         directors of the Company (even though the right so to vote has been
         suspended by the happening of such a contingency) and (c) any other
         securities into which or for which any of the securities described in
         (a) or (b) may be converted or exchanged pursuant to a plan of
         recapitalization, reorganization, merger, sale of assets or otherwise.

                  (c) The term "OTHER SECURITIES" refers to any stock (other
         than Common Stock) and other securities of the Company or any other
         person (corporate or otherwise) that the Holder of this Warrant at any
         time shall be entitled to receive, or shall have received, on the
         exercise of this Warrant, in lieu of or in addition to Common Stock, or
         that at any time shall be issuable or shall have been issued in
         exchange for or in replacement of Common Stock or Other Securities
         pursuant to Section 4 or otherwise.

         1.       EXERCISE OF WARRANT.

                  1.1      METHOD OF EXERCISE.

                  (a) This Warrant may be exercised in whole or in part (but not
         as to a fractional share of Common Stock), at any time and from time to
         time during the Exercise Period by the Holder hereof by delivery of a
         notice of exercise (a "NOTICE OF EXERCISE") substantially in the form
         attached hereto as EXHIBIT A via facsimile to the Company. Prior to
         sending the Notice of Exercise via facsimile, the Holder shall give
         Richard Schumacher notice of its intent to submit a Notice of Exercise
         by telephone (and if Mr. Schumacher is not available to be reached by
         telephone, either Kevin Quinlan or Kathi Benjamin by telephone, or such
         other person designated by the Company after the Closing Date).
         Promptly thereafter the Holder shall surrender this Warrant (if the
         entire amount of the Warrant is subject to the Notice of Exercise) to
         the Company at its principal office via overnight delivery service,
         accompanied by payment of the Purchase Price multiplied by the number
         of shares of Common Stock for which this Warrant is being exercised
         (the "EXERCISE PRICE"). Payment of the Exercise Price shall be made, at
         the option of the Holder, (i) by check or bank draft payable to the
         order of the Company, or (ii) by wire transfer to the account of the
         Company. Upon exercise, the Holder shall be entitled to receive within
         three Trading Days of the Exercise Date (as defined herein), one or
         more certificates, issued in the Holder's name or

                                       2
<PAGE>

         in such name or names as the Holder may direct, subject to the
         limitations on transfer contained herein, for the number of shares of
         Common Stock so purchased. The shares of Common Stock so purchased
         shall be deemed to be issued as of the close of business on the date on
         which the Company shall have received from the Holder payment in full
         of the Exercise Price (the "EXERCISE DATE").

                  (b) Upon exercise of a portion of this Warrant in accordance
         with the terms hereof, records showing the amount so exercised and the
         date of exercise shall be maintained on a ledger substantially in the
         form of ANNEX B attached hereto (an originally signed and executed copy
         of which shall be delivered to the Company with each Notice of
         Exercise). The Company shall maintain the originally signed and
         executed ledger and the Holder shall maintain a copy thereof. Upon
         execution of the exercise of the Warrants contemplated by the Notice of
         Exercise, the Company shall deliver to the Holder a copy of ANNEX B
         signed and executed by the Company, and the Holder shall deliver to the
         Company a copy of Annex B signed by the Holder. It is specifically
         contemplated that the Company shall act as the calculation agent for
         all exercises of this Warrant. The Holder and any assignee, by
         acceptance of this Warrant, acknowledges and agrees that, by reason of
         the provisions of this paragraph, following an exercise of a portion of
         this Warrant, the number of shares of Common Stock represented by this
         Warrant will be the amount indicated on ANNEX B attached hereto (which
         may be less than the amount stated on the face hereof).

                  (c) In the event there is a dispute as to the number of shares
         of Common Stock the Holder is entitled to receive upon exercise of this
         Warrant, the Company shall issue to the Holder the number of shares not
         in dispute and the Company and the Holder will use their best efforts
         to resolve such dispute within one Business Day following the receipt
         of a Notice of Exercise. If such dispute cannot be resolved within such
         one-day period, the Company and the Holder shall submit the dispute to
         an independent accountant mutually agreed upon by the Company and the
         Holder to make a final and binding determination of the number of
         shares owed to the Holder. The Company shall issue shares of Common
         Stock owed to Holder as a result of the resolution of the dispute
         within two Business Days following the receipt of the accountant's
         independent determination.

                  1.2 REGULATION D RESTRICTIONS. The Holder hereof represents
and warrants to the Company that it has acquired this Warrant and anticipates
acquiring the shares of Common Stock issuable upon exercise of the Warrant
solely for its own account for investment purposes and not with a view to or for
resale of such securities unless such resale has been registered with the
Commission or an applicable exemption is available therefor and provided that
the Holder shall have furnished to the Company an opinion of counsel in form and
substance reasonably satisfactory to the Company, to the effect that such
transfer is exempt from the registration requirements of the Securities Act and
any applicable state securities laws.

                  1.3 COMPANY ACKNOWLEDGMENT. The Company will, at the time of
the exercise of this Warrant, upon request of the Holder hereof, acknowledge in
writing its continuing obligation to afford to such Holder the registration
rights to which such Holder shall continue to be entitled

                                       3
<PAGE>

after such exercise in accordance with the provisions of a Registration Rights
Agreement dated the date hereof (the "Registration Rights Agreement").

                  1.4 LIMITATION ON EXERCISE. Notwithstanding the rights of the
Holder to exercise all or a portion of this Warrant as described herein, such
exercise rights shall be limited, solely to the extent set forth in the Purchase
Agreement as if such provisions were specifically set forth herein. In addition,
the number of shares of Common Stock issuable upon exercise of this Warrant is
subject to reduction as specified in Section 10.3 of the Purchase Agreement.

         2. DELIVERY OF STOCK CERTIFICATES, ETC., ON EXERCISE. As soon as
practicable after the exercise of this Warrant, and in any event within three
(3) Business Days thereafter, the Company at its expense (including the payment
by it of any applicable issue, stamp or transfer taxes) will cause to be issued
in the name of and delivered to the Holder thereof, or, to the extent
permissible hereunder, to such other person as such Holder may direct, a
certificate or certificates for the number of fully paid and nonassessable
shares of Common Stock (or Other Securities) to which such Holder shall be
entitled on such exercise, plus, in lieu of any fractional share to which such
Holder would otherwise be entitled, cash equal to such fraction multiplied by
the then applicable Purchase Price, together with any other stock or other
securities and property (including cash, where applicable) to which such Holder
is entitled upon such exercise pursuant to Section 1 or otherwise.

         3. ADJUSTMENT FOR EXTRAORDINARY EVENTS. The Purchase Price to be paid
by the Holder upon exercise of this Warrant, and the consideration to be
received upon exercise of this Warrant, shall be adjusted in case at any time or
from time to time pursuant to Article 11 of the Purchase Agreement as if such
provisions were specifically set forth herein.

         4. NO IMPAIRMENT. The Company will not, by amendment of its Certificate
of Incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any other
voluntary action, avoid or seek to avoid the observance or performance of any of
the terms of this Warrant, but will at all times in good faith assist in the
carrying out of all such terms and in the taking of all such action as may be
necessary or appropriate in order to protect the rights of the Holder of this
Warrant against impairment. Without limiting the generality of the foregoing,
the Company (a) will not increase the par value of any shares of stock
receivable on the exercise of this Warrant above the amount payable therefor on
such exercise, (b) will take all such action as may be necessary or appropriate
in order that the Company may validly and legally issue fully paid and
unassessable shares of stock on the exercise of this Warrant, and (c) will not
transfer all or substantially all of its properties and assets to any other
person (corporate or otherwise), or consolidate with or merge into any other
person or permit any such person to consolidate with or merge into the Company
(if the Company is not the surviving person), unless such other person shall
expressly assume in writing and will be bound by all the terms of this Warrant.

         5. CERTIFICATE AS TO ADJUSTMENTS. In each case of any adjustment or
readjustment in the shares of Common Stock (or Other Securities) issuable on the
exercise of this Warrant, the Company will promptly cause its principal
financial officer to compute such adjustment or readjustment in accordance with
the terms of this Warrant and prepare a certificate setting forth such
adjustment or

                                       4
<PAGE>

readjustment and showing in detail the facts upon which such adjustment or
readjustment is based, including a statement of (a) the consideration received
or receivable by the Company for any additional shares of Common Stock (or Other
Securities) issued or sold or deemed to have been issued or sold, (b) the number
of shares of Common Stock (or Other Securities) outstanding or deemed to be
outstanding, and (c) the Purchase Price and the number of shares of Common Stock
to be received upon exercise of this Warrant, in effect immediately prior to
such issue or sale and as adjusted and readjusted as provided in this Warrant.
The Company will forthwith mail a copy of each such certificate to the Holder of
this Warrant, and will, on the written request at any time of the Holder of this
Warrant, furnish to such Holder a like certificate setting forth the Purchase
Price at the time in effect and showing how it was calculated.

         6.       NOTICES OF RECORD DATE, ETC.

                  In the event of

                           (a) any taking by the Company of a record of the
         Holders of any class of securities for the purpose of determining the
         Holders thereof who are entitled to receive any dividend or other
         distribution, or any right to subscribe for, purchase or otherwise
         acquire any shares of stock of any class or any other securities or
         property, or to receive any other right, or

                           (b) any capital reorganization of the Company, any
         reclassification or recapitalization of the capital stock of the
         Company or any transfer of all or substantially all the assets of the
         Company to or consolidation or merger of the Company with or into any
         other Person, or

                           (c) any voluntary or involuntary dissolution,
         liquidation or winding-up of the Company,

then and in each such event the Company will mail or cause to be mailed to the
Holder of this Warrant a notice specifying (i) the date on which any such record
is to be taken for the purpose of such dividend, distribution or right, and
stating the amount and character of such dividend, distribution or right, and
(ii) the date on which any such reorganization, reclassification,
recapitalization, transfer, consolidation, merger, dissolution, liquidation or
winding-up is to take place, and the time, if any, as of which the Holders of
record of Common Stock (or Other Securities) shall be entitled to exchange their
shares of Common Stock (or Other Securities) for securities or other property
deliverable on such reorganization, reclassification, recapitalization,
transfer, consolidation, merger, dissolution, liquidation or winding-up. Such
notice shall be mailed at least 20 days prior to the date specified in such
notice on which any action is to be taken.

         7. RESERVATION OF STOCK, ETC. ISSUABLE ON EXERCISE OF WARRANT. The
Company will at all times reserve and keep available, solely for issuance and
delivery on the exercise of this Warrant, all shares of Common Stock (or Other
Securities) from time to time issuable on the exercise of this Warrant.

                                       5
<PAGE>

         8. EXCHANGE OF WARRANT. On surrender for exchange of this Warrant,
properly endorsed and in compliance with the restrictions on transfer set forth
in the legend on the face of this Warrant, to the Company, the Company at its
expense will issue and deliver to or on the order of the Holder thereof a new
Warrant of like tenor, in the name of such Holder or as such Holder (on payment
by such Holder of any applicable transfer taxes) may direct, calling in the
aggregate on the face or faces thereof for the number of shares of Common Stock
called for on the face of the Warrant so surrendered or for such lesser number
of shares of Common Stock as may be reflected on the Warrant Exercise Ledger
attached as Annex B.

         9. REPLACEMENT OF WARRANT. On 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 of this
Warrant, on delivery of an indemnity agreement or security reasonably
satisfactory in form and amount to the Company or, in the case of any such
mutilation, on surrender and cancellation of this Warrant, the Company at its
expense will execute and deliver, in lieu thereof, a new Warrant of like tenor.

         10. REMEDIES. The Company stipulates that the remedies at law of the
Holder of this Warrant in the event of any default or threatened default by the
Company in the performance of or compliance with any of the terms of this
Warrant are not and will not be adequate, and that such terms may be
specifically enforced by a decree for the specific performance of any agreement
contained herein or by an injunction against a violation of any of the terms
hereof or otherwise.

         11. NEGOTIABILITY, ETC.. This Warrant is issued upon the following
terms, to all of which each Holder or owner hereof by the taking hereof consents
and agrees:

                   (a) until this Warrant is transferred on the books of the
Company, the Company may treat the registered Holder hereof as the absolute
owner hereof for all purposes, notwithstanding any notice to the contrary; and

                  (b) this Warrant may not be sold, transferred or assigned
except pursuant to an effective registration statement under the Securities Act
or pursuant to an applicable exemption therefrom.

         12. REGISTRATION RIGHTS. The Company is obligated to register the
shares of Common Stock issuable upon exercise of this Warrant in accordance with
the terms of the Registration Rights Agreement.

         13. WARRANT REDEMPTION. Upon occurrence of the events described in
Sections 3.4 and 10.4(c) of the Purchase Agreement, the Company, at the request
of Holder, shall redeem all outstanding Warrants that remain unexercised at a
redemption price equal to the greater of (x) an appraised value of the Warrants,
as determined by Black Sholes, on the date they are called for redemption and
(y) the number of Warrants being redeemed multiplied by the excess of (A) the
average Closing Bid Price of the Common Stock for the five trading days
immediately prior to the date that the Warrants are called for redemption over
(B) the exercise price of the Warrants.

                                       6
<PAGE>

         14. NOTICES, ETC. All notices and other communications from the Company
to the Holder of this Warrant shall be mailed by first class registered or
certified mail, postage prepaid, at such address as may have been furnished to
the Company in writing by such Holder or, until any such Holder furnishes to the
Company any address, then to, and at the address of, the last Holder of this
Warrant who has so furnished an address to the Company.

         15. MISCELLANEOUS. This Warrant and any term hereof may be changed,
waived, discharged or terminated only by an instrument in writing signed by the
party against which enforcement of such change, waiver, discharge or termination
is sought. This Warrant shall be construed and enforced in accordance with and
governed by the internal laws of the State of Massachusetts. The headings in
this Warrant are for the purposes of reference only, and shall not limit or
otherwise affect any of the terms hereof. The invalidity or unenforceability of
any provision hereof shall in no way affect the validity or enforceability of
any other provision.

                                       7
<PAGE>

DATED as of August 25, 2000.

                                      BOSTON BIOMEDICA, INC.

                                      By: /s/ Kevin W. Quinlan
                                          -------------------------------------
                                      Name: Kevin W. Quinlan
                                      Title: President

                                       8
<PAGE>

                                    EXHIBIT A

                        FORM OF NOTICE EXERCISE - WARRANT

                       (To be executed only upon exercise
                       of the Warrant in whole or in part)

To ____________________________________________

         The undersigned registered Holder of the accompanying Warrant, hereby
exercises such Warrant or portion thereof for, and purchases thereunder,
__________ (1) shares of Common Stock (as defined in such Warrant) and herewith
makes payment therefor in the amount and manner set forth below, as of the date
written below. The undersigned requests that the certificates for such shares of
Common Stock be issued in the name of, and delivered to, ______________________
whose address is ____________________________________________________________.
The Exercise Price is paid as follows:

         / /  Certified Bank draft payable to the Company in the
              amount of $_____________.
         / /  Wire transfer to the account of the Company in the
              amount of $___________.

       Upon exercise pursuant to this Notice of Exercise, the Holder will be in
compliance with the Limitation on Exercise (as defined in the Securities
Purchase Agreement pursuant to which this Warrant was issued).

       The Holder of the shares of Common Stock received upon exercise of the
Warrant (the "Common Shares"), covenants and agrees that the Common Shares are
being acquired as an investment and not with a view to the distribution thereof
in violation of the Securities Act and that the Common Shares may not be
transferred, sold, assigned, hypothecated or otherwise disposed of, in whole or
in part except as provided in the legend on the first page of this Warrant and
provided that the Holder shall have furnished the Company an opinion of counsel
in form and substance reasonably acceptable to the Company to the effect that
such transfer is exempt from the registration requirements of the Securities Act
and any applicable state securities laws.*

Date:
     ------------------------------    -----------------------------------------
                                       (Name must conform to name of Holder as
                                       specified on the face of the Warrant)
                                       By:
                                          --------------------------------------
                                          Name:
                                               ---------------------------------
                                          Title:
                                                --------------------------------

                                       Address of Holder:
                                                         -----------------------
                                                         -----------------------

Date of exercise:
                 --------------
* If shares of common Stock are to be issued to anyone other than the
  Holder, this covenant and representation must be made by such other
  Person.

--------------------
         (1)Insert the number of shares of Common Stock as to which the
accompanying Warrant is being exercised. In the case of a partial exercise, a
new Warrant or Warrants will be issued and delivered, representing the
unexercised portion of the accompanying Warrant, to the Holder surrendering the
same.

<PAGE>

                                     ANNEX B

                             WARRANT EXERCISE LEDGER
<TABLE>
<CAPTION>
-----------------------------------------------------------------------------------------------------------------------------------
                     ORIGINAL NUMBER OF         WARRANTS        EXERCISE PRICE       NEW BALANCE            ISSUER          HOLDER
    DATE                 WARRANTS              EXERCISED            PAID             OF WARRANTS           INITIALS        INITIALS
-----------------------------------------------------------------------------------------------------------------------------------
<S>                  <C>                       <C>              <C>                  <C>                   <C>             <C>

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

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

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

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

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

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

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

-----------------------------------------------------------------------------------------------------------------------------------
</TABLE>

BOSTON BIOMEDICA, INC.                              HOLDER:

By:      _______________________                    By: _____________________
Name:     _______________________                   Name:____________________
Title:   ________________________                   Title:___________________

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