<PAGE>

THE SECURITIES REPRESENTED BY THIS WARRANT CERTIFICATE AND THE SHARES OF STOCK
ISSUABLE UPON EXERCISE HEREOF HAVE BEEN ACQUIRED FOR INVESTMENT AND HAVE NOT
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY
SECURITIES LAWS OF A STATE OR OTHER JURISDICTION AND MAY NOT UNDER ANY
CIRCUMSTANCES BE SOLD, TRANSFERRED OR OTHERWISE DISPOSED OF (OTHER THAN TO AN
AFFILIATE OR AS OTHERWISE PERMITTED BY THIS WARRANT CERTIFICATE PURSUANT TO
WHICH THEY WERE ISSUED) EXCEPT PURSUANT TO (i) AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE ACT AND ANY APPLICABLE STATE SECURITIES OR BLUE SKY LAWS, OR
(ii) TO THE EXTENT APPLICABLE, RULE 144 UNDER THE ACT (OR ANY SIMILAR RULE UNDER
THE ACT RELATING TO THE DISPOSITION OF SECURITIES) TOGETHER WITH AN OPINION OF
COUNSEL SATISFACTORY TO GENEREX BIOTECHNOLOGY CORPORATION THAT REGISTRATION IS
NOT REQUIRED UNDER THE ACT OR APPLICABLE STATE SECURITIES LAWS.

                        GENEREX BIOTECHNOLOGY CORPORATION


                           WARRANT TO PURCHASE SHARES
                                 OF COMMON STOCK


                  THIS CERTIFIES THAT, for value received, Elan International
Services, Ltd., a Bermuda exempted limited liability company, or its permitted
transferees and successors as provided herein (each, a "Holder"), is entitled to
subscribe for and purchase up to 75,000 shares, as adjusted pursuant to Section
4 (the "Shares"), of the fully paid and nonassessable common stock, par value
U.S.$.001 per share (the "Common Stock"), of Generex Biotechnology Corporation,
a Delaware corporation (the "Company"), at the price per share equal to a 125%
premium over the Original Issue Date Base Price (as defined below) (such price,
and such other prices that shall result from time to time, from the adjustments
specified in Section 4, the "Warrant Price"), subject to the provisions and upon
the terms and conditions hereinafter set forth. The "Original Issue Date Base
Price" shall mean the average closing price per share of publicly traded shares
of Common Stock over the sixty day period immediately preceding the date of this
Warrant (the "Closing Date") as reported on the Nasdaq National Market System or
a national securities exchange. The Warrant Price shall be equal to $25.15 per
share.

                  1. Term. Subject to the limitations set forth in Sections 3
and 4, the purchase right represented by this Warrant is exercisable, in whole
or in part, at any time, and from time to time, from and after the date hereof
and until 5:00 p.m. Eastern Standard Time, January 16, 2007. To the extent not
exercised at 5:00 p.m. Eastern Standard Time on January 16, 2007, this Warrant
shall completely and automatically terminate and expire, and thereafter it shall
be of no force or effect.




<PAGE>


                  2. Method of Exercise; Payment; Issuance of New Warrant. (a)
The purchase right represented by this Warrant may be exercised by the Holder,
in whole or in part and from time to time, by the surrender of this Warrant
(with the notice of exercise form attached hereto as Annex A duly executed) at
the principal office of the Company and by the payment to the Company of an
amount, at the option of the Holder, (i) in cash or other immediately available
funds, (ii) by the surrender of this Warrant (or a portion hereof) in accordance
with the terms hereof but without payment in cash (a "Cashless Exercise") or
(iii) with any combination of (i) and (ii). The number of shares of Common Stock
issuable in respect of a Cashless Exercise shall be 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 in
                                            respect of a Cashless Exercise

                                            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 in
                                            connection with such Cashless
                                            Exercise (at the date of such
                                            calculation)

                                            A = the Fair Market Value (as
                                            defined below) of one share of the
                                            Company's Common Stock (at the date
                                            of such calculation)

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

                  The "Fair Market Value" of one share of Common Stock shall be
determined by the Company's Board of Directors in good faith and certified in a
Board resolution (taking into account the most recently or concurrently
completed arm's length transaction between the Company and an unaffiliated third
party the closing of which occurs within the six months preceding or on the date
of such calculation, if any) and shall be reasonably agreed to by the Holder
(provided, that in the event the Company and the Holder do not agree on the Fair
Market Value, the parties shall jointly appoint an independent third party to
determine the Fair Market Value); provided, however, that in the event the
Common Stock is traded on a securities exchange, the Nasdaq National Market or
the Nasdaq SmallCap Market, the Fair Market Value shall be deemed to be the
average of the closing sale prices for the Common Stock over the fifteen (15)
day trading period (or such shorter period for which closing sale prices are
available if the Common Stock commenced trading during such period) ending on
the trading day prior to the date of exercise of this Warrant.


                                       -2-


<PAGE>


                  (b) The persons or entities in whose name(s) any
certificate(s) representing Shares shall be issuable upon exercise of this
Warrant shall be deemed to have become the holder(s) of record of, and shall be
treated for all purposes as the record holder(s) of, the Shares represented
thereby (and such Shares shall be deemed to have been issued) immediately prior
to the close of business on the date or dates upon which this Warrant is
properly exercised and full payment for the Shares acquired pursuant to such
exercise is made. Upon any exercise of the rights represented by this Warrant,
certificates for the Shares purchased shall be delivered to the holder hereof as
soon as possible and in any event within 30 days of receipt of such notice and
payment, and unless this Warrant has been fully exercised or expired, a new
Warrant representing the portion of Shares, if any, with respect to which this
Warrant shall not then have been exercised shall also be issued to the holder
hereof as soon as possible and in any event within such 30-day period.

                  3. Stock Fully Paid, Reservation of Shares. All Shares that
may be issued upon the exercise of this Warrant will, upon issuance, be duly and
validly authorized and issued, fully paid and nonassessable, and will be free
from all transfer taxes (except for taxes resulting from the issuance of shares
to a person other than the Holder), liens and charges with respect to the issue
thereof and assuming payment of the Warrant Price for all Shares so purchased,
legally and validly owned by the Holder. During the period within which this
Warrant may be exercised, the Company will at all times have authorized, and
reserved for the purpose of the issue upon the exercise of the purchase 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. Adjustment of Warrant Price and Number of Shares. The
number and kind of securities purchasable upon the exercise of this Warrant and
the Warrant Price shall be subject to the adjustment from time to time upon the
occurrence of certain events, as follows:

                  (a) Reclassification, Etc. In case of (i) any
reclassification, reorganization, change or conversion of securities of the
class issuable upon exercise of this Warrant (other than a change in par value,
or from par value to no par value) into other shares or securities of the
Company, or (ii) any merger or consolidation of the Company with or into another
entity (other than a merger or consolidation with another entity in which the
Company is the acquiring and the surviving entity and that does not result in
any reclassification or change of outstanding securities issuable upon exercise
of this Warrant), or (iii) any sale of all or substantially all the assets of
the Company, then the Company, or such successor or purchasing entity, as the
case may be, shall duly execute and deliver to the holder of this Warrant a new
Warrant or a supplement hereto (in form and substance reasonably satisfactory to
the holder of this Warrant), so that the Holder shall have the right to receive,
at a total purchase price not to exceed that payable upon the exercise of the
unexercised portion of this Warrant, and in lieu of the shares of Common Stock
theretofore issuable upon the exercise of this Warrant, the kind and amount of
shares of stock and other securities, receivable upon such reclassification,
reorganization, change or conversion by a holder of the number of shares of



                                       -3-
<PAGE>


Common Stock then purchasable under this Warrant. Such new Warrant shall provide
for adjustments that shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Section 4. The provisions of this Section 4(a)
shall similarly attach to successive reclassifications, reorganizations,
changes, and conversions.

                  (b)  Stock Dividends; Etc.
                       --------------------

                    (i) If at any time prior to the earlier of the exercise or
         expiration hereof the Company shall fix a record date for the
         effectuation of a split or subdivision of the outstanding shares of
         Common Stock or the determination of holders of Common Stock entitled
         to receive a dividend or other distribution payable in additional
         shares of Common Stock or other securities or property or rights
         convertible into, or entitling the holder thereof to receive directly
         or indirectly, any of the foregoing (hereinafter referred to as "Common
         Stock Equivalents") without payment of any consideration by such holder
         for the additional shares of Common Stock or the Common Stock
         Equivalents (including the additional shares of Common Stock issuable
         upon conversion or exercise thereof) or with payment that is less than
         the lower of (x) the then-Fair Market Value of the Common Stock
         (including, in the case of Common Stock Equivalents, on an as-converted
         basis) and (y) the Warrant Price then in effect, then and in each case,
         this Warrant shall be for, in addition to the number of shares of the
         Common Stock otherwise deliverable upon exercise of this Warrant, and
         without adjustment to the Warrant Price, the amount of such additional
         shares of Common Stock and any Common Stock Equivalents that the holder
         hereof would have received or become entitled to receive on the same
         terms and conditions as if such holder had been a holder of record of
         such Common Stock as shall have been deliverable immediately prior to
         such record date pursuant to the terms of this Section 4; provided that
         the upon the exercise, in addition to the Warrant Price, the Holder
         shall pay any consideration which would have been payable for such
         Common Stock or Common Stock Equivalents.

                   (ii) If the Company at any time during which this Warrant
         remains outstanding and unexpired shall subdivide or combine its Common
         Stock, (A) in the case of a subdivision, the Warrant Price shall be
         proportionately decreased and the number of Shares purchasable
         hereunder shall be proportionately increased, and (B) in the case of a
         combination, the Warrant Price shall be proportionately increased and
         the number of Shares purchasable hereunder shall be proportionately
         decreased.

                  (c) Other Distributions. In the event the Company shall
declare a distribution payable in securities of other persons, evidences of
indebtedness issued by the Company or other persons, assets, cash (excluding
cash dividends declared out of retained earnings) or options or rights not
referred to in the previous subsection (b), then, in each such case for the
purpose of this subsection (c), upon exercise of this Warrant, the Holder shall
be entitled to a proportionate share of any such distribution as though such



                                       -4-

<PAGE>


Holder was a holder of the number of shares of Common Stock of the Company into
which this Warrant would be convertible as of the record date fixed for the
determination of the holders of Common Stock of the Company entitled to receive
such distribution.

                  (d) No Impairment. The Company will not, by amendment of its
Certificate of Incorporation or bylaws or through any reorganization,
recapitalization, 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 to be observed or performed
hereunder by the Company, but will at all times in good faith assist in the
carrying out of all the provisions of this Section 4 and in the taking of all
such action as may be necessary or appropriate in order to protect the rights of
the Holder against impairment.

                  (e) Notice of Adjustments. Whenever the Warrant Price or the
number of Shares purchasable hereunder shall be adjusted pursuant to this
Section 4, the Company shall prepare a certificate setting forth, in reasonable
detail, the event requiring the adjustment, the amount of the adjustment, the
method by which such adjustment was calculated. Such certificate shall be signed
by its chief financial officer and shall be delivered to the Holder.

                  (f) Fractional Shares. No fractional shares of Common Stock
will be issued in connection with any exercise hereunder, but in lieu of such
fractional shares the Company shall make a cash payment therefor based on the
fair market value of the Common Stock on the date of exercise as reasonably
determined in good faith by the Company's Board of Directors.

                  (g) Cumulative Adjustments. No adjustment in the Warrant Price
shall be required under this Section 4 until cumulative adjustments result in a
concomitant change of 1% or more of the Warrant Price or in the number of shares
of Common Stock purchasable upon exercise of this Warrant as in effect prior to
the last such adjustment; provided, however, that any adjustment that by reason
of this Section 4 are not required to be made shall be carried forward and taken
into account in any subsequent adjustment. All calculations under this Section 4
shall be made to the nearest cent or to the nearest one-hundredth of a share, as
the case may be.

                  5. Compliance with Securities Act; Disposition of Warrant or
Shares of Common Stock.

                  (a) The Holder, by acceptance hereof, agrees that this Warrant
and the Shares to be issued upon exercise hereof are being acquired for
investment and that such holder will not offer, sell or otherwise dispose of
this Warrant or any Shares to be issued upon exercise hereof except under
circumstances which will not result in a violation of applicable securities laws
and which are in compliance with the provisions of the legend set forth below.
Upon exercise of this Warrant, unless the Shares being acquired are registered
under the Securities Act of 1933, as amended (the "Act"), or an exemption from
the registration requirements of such Act is available, the Holder shall confirm




                                       -5-
<PAGE>

in writing, by executing an instrument in form reasonably satisfactory to the
Company, that the Shares so purchased are being acquired for investment and not
with a view toward distribution or resale and that the Holder is an accredited
investor, as defined in Regulation D under the Act. This Warrant and all Shares
issued upon exercise of this Warrant (unless registered under the Act) shall be
stamped or imprinted with a legend in substantially the following form:

         "THE SECURITIES REPRESENTED BY THIS WARRANT CERTIFICATE AND THE SHARES
         OF STOCK ISSUABLE UPON EXERCISE HEREOF HAVE BEEN ACQUIRED FOR
         INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF
         1933, AS AMENDED (THE "ACT"), OR ANY SECURITIES LAWS OF A STATE OR
         OTHER JURISDICTION AND MAY NOT UNDER ANY CIRCUMSTANCES BE SOLD,
         TRANSFERRED OR OTHERWISE DISPOSED OF (OTHER THAN TO AN AFFILIATE OR AS
         OTHERWISE PERMITTED BY THIS WARRANT CERTIFICATE PURSUANT TO WHICH THEY
         WERE ISSUED) EXCEPT PURSUANT TO (i) AN EFFECTIVE REGISTRATION STATEMENT
         UNDER THE ACT AND ANY APPLICABLE STATE SECURITIES OR BLUE SKY LAWS, OR
         (ii) TO THE EXTENT APPLICABLE, RULE 144 UNDER THE ACT (OR ANY SIMILAR
         RULE UNDER THE ACT RELATING TO THE DISPOSITION OF SECURITIES) TOGETHER
         WITH AN OPINION OF COUNSEL SATISFACTORY TO GENEREX BIOTECHNOLOGY
         CORPORATION THAT REGISTRATION IS NOT REQUIRED UNDER THE ACT OR
         APPLICABLE STATE SECURITIES LAWS."

                  (b)

                    (i) This Warrant may be transferred or assigned, in whole or
         in part, by Elan International Services, Ltd. to its affiliates and
         subsidiaries, including any special purpose financing or similar
         vehicle affiliate. Other than as set forth in the preceding sentence,
         this Warrant may not be transferred or assigned by either party without
         the prior written consent of the other. Subject to the foregoing, this
         Warrant and all of the provisions hereof shall be binding upon and
         inure to the benefit of the parties hereto and their respective
         successors and permitted assigns; provided, however, that the
         transferor and the Company shall continue to be liable and obligated
         for their respective obligations hereunder after any such assignment.

                   (ii) With respect to any offer, sale or other disposition of
         this Warrant or any Shares acquired pursuant to the exercise of this
         Warrant prior to registration of such Shares, the Holder shall give
         written notice to the Company prior thereto, describing briefly the
         manner thereof, together with a written opinion of counsel reasonably





                                       -6-

<PAGE>

         acceptable to the Company (as to content of such opinion and the
         identity of such counsel), if requested by the Company, to the effect
         that such offer, sale or other disposition may be effected without
         registration or qualification (under the Securities Act as then in
         effect or any federal or state law then in effect) of this Warrant or
         such Shares and indicating whether or not under the Act certificates
         for this Warrant or such Shares to be sold or otherwise disposed of
         require any restrictive legend as to applicable restrictions on
         transferability in order to ensure compliance with the Act. In
         addition, the Company may, upon the reasonable advice of its counsel,
         require the prospective transferee to execute documentation verifying
         as to the transferees investment intent and status as an accredited
         investor. Promptly upon receiving such written notice, reasonably
         satisfactory opinion and other materials as to investment intent and
         status, if so requested, the Company, as promptly as practicable, shall
         notify such Holder that such Holder may sell or otherwise dispose of
         this Warrant or such Shares, all in accordance with the terms of the
         notice delivered to the Company. Each certificate representing this
         Warrant or the Shares thus transferred shall bear a legend as to the
         applicable restrictions on transferability in order to insure
         compliance with the Securities Act, unless in the aforesaid opinion of
         counsel for the Holder such legend is not required in order to insure
         compliance with the Securities Act. The Company may issue stop transfer
         instructions to its transfer agent in connection with such
         restrictions.

                  (iii) The shares of Common Stock for which this Warrant is
         exercisable are entitled to the benefit of certain registration rights
         as set forth in a Registration Rights Agreement dated as of the date
         hereof between the Company and the initial Holder named herein.

                  6. Rights as Shareholders. No Holder, as such, shall be
entitled to vote or receive dividends or be deemed the holder of Shares or any
other securities of the Company which may at any time be issuable on the
exercise hereof for any purpose, nor shall anything contained herein be
construed to confer upon the Holder, as such, any right to vote for the election
of directors or upon any matter submitted to shareholders at any meeting
thereof, or to receive notice of meetings, or to receive dividends or
subscription rights or otherwise until this Warrant is exercised and the Shares
purchasable upon the exercise hereof shall have become deliverable, as provided
herein.

                  7. Representations and Warranties. The Company represents and
warrants to the Holder as follows:

                  (a) The Company has all requisite corporate power and
authority to authorize and execute this Warrant and the certificates evidencing
the Shares and to perform all obligations and undertakings under this Warrant
and the certificates evidencing the Shares;

                  (b) This Warrant has been duly authorized and executed by the
Company and is a valid and binding obligation of the Company enforceable in
accordance with its terms;



                                       -7-

<PAGE>


                  (c) The Shares have been duly authorized and reserved for
issuance by the Company and, when issued in accordance with the terms hereof,
will be validly issued, fully paid and nonassessable; and

                  (d) The execution and delivery of this Warrant are not, and
the issuance of the Shares upon exercise of this Warrant in accordance with the
terms hereof will not be, inconsistent with the Company's Certificate of
Incorporation or bylaws, as amended, and do not and will not constitute a
default under, any indenture, mortgage, contract or other instrument of which
the Company is a party or by which it is bound.

                  8. Miscellaneous. (a) This Warrant may not be modified or
amended, or any provisions hereof waived, except by written agreement of the
Company and the Holder.

                  (b) All notices, demands and requests of any kind to be
delivered to any party in connection with this Note shall be in writing and
shall be deemed to have been duly given if personally or hand delivered or if
sent by an internationally-recognized overnight delivery courier or by
registered or certified mail, return receipt requested and postage prepaid, or
by facsimile transmission addressed as follows:

           (i)    if to the Company, to:

                         Generex Biotechnology Corporation
                         32 Harbour Square
                         Suite 202
                         Toronto Ontario Canada
                         Attention:  Chief Executive Officer
                         Facsimile:  (416) 364-9363

                  with a copy to:

                         Eckert Seamans Cherin Mellot
                         1515 Market Street
                         9th Floor
                         Philadelphia, PA 19102
                         Attention:  John G. Chou
                         Facsimile:  (215) 851-8383



                                       -8-

<PAGE>

          (ii)    if to EIS, to:

                         Elan International Services, Ltd.
                         102 St. James Court
                         Flatts, Smiths Parish
                         Bermuda FL 04
                         Attention:  Chief Executive Officer
                         Facsimile:  (441) 292-2224

                  with a copy to:

                           Cahill Gordon & Reindel
                           80 Pine Street
                           New York, NY 10005
                           Attention:  William M. Hartnett
                           Facsimile:  (212) 269-5420


                  (c) The Company covenants to the Holder 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 a bond or indemnity reasonably satisfactory to the
Company, or in the case of any such mutilation upon surrender and cancellation
of such Warrant, the Company will make and deliver a new Warrant, of like tenor,
in lieu of the lost, stolen, destroyed or mutilated Warrant.

                  (d) The descriptive headings of the several sections and
paragraphs contained in this Warrant are for reference purposes only and shall
not affect in anyway the meaning or interpretation of this Warrant.

                  (e) This Warrant shall be governed by and construed in
accordance with the internal laws of the State of New York, without giving
effect to the principles of conflicts of laws. Any dispute under this Warrant
that is not settled by mutual consent shall be finally adjudicated by any
federal or state court sitting in the City, County and State of New York, and
the Company consents to the exclusive jurisdiction of such courts (or any
appellate court therefrom) over any such dispute.

                  (f) This Warrant may be executed in any number of
counterparts, and each such counterpart hereof shall be deemed to be an original
instrument, but all such counterparts together shall constitute one Warrant.
This Warrant may be signed and delivered to the other party by a facsimile
transmission; such transmission shall be deemed a valid signature.

                  (g) Each of the parties shall be responsible for its own costs
and expenses incurred in connection with the transactions contemplated hereby.

                            [Signature page follows]





                                       -9-
<PAGE>


                  IN WITNESS WHEREOF, the Company has executed this Warrant as
of the 16th day of January, 2001.

                                                 GENEREX BIOTECHNOLOGY
                                                 CORPORATION




                                             By: /s/ E. Mark Perri
                                                 -------------------------------
                                                 Name:   E. Mark Perri
                                                 Tittle: Chief Financial Officer














<PAGE>



                                                                         Annex A
                                                                         -------

NOTICE OF EXERCISE
------------------

To:      Generex Biotechnology Corporation

1. The undersigned hereby elects to purchase _______ shares of Common Stock of
Generex Biotechnology Corporation pursuant to the terms of the attached Warrant,
and tenders herewith full payment of the purchase price of such shares, in cash
or other immediately available funds.

                  2. Please issue a certificate or certificates representing
said shares in the name of the undersigned or in such other name or names as are
specified below:

_____________________________________________________ (Name)

_____________________________________________________

_____________________________________________________ (Address)


                  3. The undersigned represents that the aforesaid shares are
being acquired for the account of the undersigned for investment and not with a
view to, or for resale in connection with, the distribution thereof and that the
undersigned has no present intention of distributing or reselling such shares.


Signature: __________________________________________

Name: _______________________________________________

Address: ____________________________________________

         ____________________________________________

         ____________________________________________



Social Security or taxpayer identification number:

______________________________________________





                                       11