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                                                                    EXHIBIT 99.2

                              OMNIBUS AGREEMENT II

         OMNIBUS AGREEMENT II (this "Agreement"), dated as of May 16, 2002, by
and between BOSTON LIFE SCIENCES, INC., a Delaware corporation (the "Company"),
and BROWN SIMPSON PARTNERS I, LTD., a Cayman Islands company (the "Holder").

         Reference is made to each of the Series A and Series B Stock Purchase
Warrants set forth on Schedule I hereto (each a "Warrant", together the
"Warrants") issued by the Company and held by the Holder, initially issued for
the purchase of an aggregate of 1,690,000 shares of the Company's common stock,
par value $.01 per share (the "Common Stock"), subject to certain adjustments as
set forth in the Warrants. Capitalized terms used herein but not otherwise
defined herein shall have the meanings ascribed to such terms in the Warrants or
the transaction documents related thereto.

         WHEREAS, in March 2002, the Company entered into a private placement
pursuant to which it sold, inter alia, $3,400,000 of the Common Stock to
individual and institutional investors at a purchase price of $2.15 per share
(the "Issuance");

         WHEREAS, the Issuance triggered certain adjustments to the Warrants in
accordance with the terms of the Warrants (the "Adjustments"); and

         WHEREAS, the purpose of this Agreement is to set forth the Adjustments,
as well as other agreements between the Company and the Holder.

         NOW, THEREFORE, in consideration of the mutual covenants and conditions
set forth in this Agreement and other good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged, the Company and the
Holder hereby agree as follows:

         A.  Warrant Shares. The Company and the Holder each hereby acknowledge
and agree that the number of Warrant Shares with respect to each Warrant shall
be adjusted as set forth on Schedule I hereto and that the number of Warrants
Shares set forth in the first sentence of Section 2 of each Warrant shall be
adjusted accordingly.

         B.  Exercise Price. The Company and the Holder each hereby acknowledge
and agree that Section 3(a) of each Warrant shall be null and void and of no
further force and effect, and replaced in its entirety with the following:

         "3. Exercise Price. The initial per share exercise price of this
Warrant, representing the price per share at which the shares of stock issuable
upon exercise of this Warrant may be purchase, is $2.15, subject to adjustment
from time to time pursuant to the provisions of Section 6 hereof (the "Exercise
Price")."

         C.  Adjustment of Number of Shares. The Company and the Holder each
further hereby acknowledge and agree that Section 6(i) of each Warrant only
shall apply to situations where the Company raises cash through the issuance of
shares of its Common Stock or options, warrants or other securities convertible
or exchangeable therefor (other than Excluded Securities). The Issuance is such
an issuance.

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         D.  Certain Events. The Company and the Holder each further hereby
acknowledge and agree that Section 6(h)(i)(D)(V) ("Certain Events") shall be
deleted and shall have no force and effect.

         E.  Continuing Force and Effect. All other provisions of the Warrants,
except as otherwise specifically set forth herein, shall remain in full force
and effect.

         F.  Registration Statement. The current registration statement for the
Warrants, which is presently effective, shall remain effective in accordance
with the terms of the Registration Rights Agreement dated September 22, 1999,
among the Company and the Purchasers as set forth therein.

         G.  Replacement Warrants. The Company further acknowledges and agrees
that within five (5) days of the date first set forth above, it shall mark and
initial changes to the Warrants to reflect the terms set forth herein, but, at
any time, the Holder may request, and the Company shall promptly provide, new,
replacement warrants reflecting the changes set forth herein. The Company
acknowledges that such new, replacement warrants are not necessary for the
exercise of the Warrants in accordance with the provisions set forth herein and
therein.

         H.  Trading Restrictions.

             (i)   The Holder hereby acknowledges and agrees that, through and
including December 31, 2003, it only shall sell shares of the Common Stock
(including shares of the Common Stock issuable upon the exercise of the
Warrants) in accordance with the following:

          .  On any day when the Common Stock trades fewer than 100,001 shares,
             the Holder may sell up to seventeen percent (17%) of the daily
             volume (on a net basis, i.e., including sales and purchases) as
             traded on the NASDAQ or a Subsequent Market (the "Daily Volume");
          .  On any day when the Common Stock trades between 100,001 and 150,000
             shares, the Holder may sell up to twenty five percent (25%) of the
             Daily Volume (on a net basis);
          .  On any day when the Common Stock trades between 150,001 and 300,000
             shares, the Holder may sell up to thirty percent (30%) of the Daily
             Volume (on a net basis);
          .  On any day when the Common Stock trades between 300,001 and 700,000
             shares, the Holder may sell up to thirty five percent (35) of the
             Daily Volume (on a net basis); and
          .  On any day when the Common Stock trades more than 700,000 shares,
             the Holder may sell up to forty five percent (45%) of the Daily
             Volume (on a net basis);

provided further, however, that on any Trading Day when the Common Stock closes
above $8.00 per share, each of the above percentages shall be increased by five
percent (5%) for that Trading Day; provided further, however, that on any
Trading Day when the Common Stock closes above $10.00 per share, each of the
above percentages shall be increased by ten percent (10%) for that Trading Day;
provided further, however, that on any Trading Day when the Common Stock closes
above $12.00 per share, there shall be no restriction on the number of shares of
the Common Stock that the Holder may sell on that Trading Day. (The trading
activity set forth in

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the foregoing five bullet points hereinafter shall be referred to as the
"Permitted Sales"). Nothing contained herein shall restrict the ability of the
Holder to sell any number of shares of the Common Stock or any number of the
Warrants or the Warrant Shares in direct placement(s) with a single purchaser or
group of purchasers, such direct placement(s) to be made on an off-market basis.

             (ii)  The Holder hereby agrees that, without the prior written
consent of the Company, neither it nor its affiliates will, through and
including December 31, 2003, in excess of the Permitted Sales, (i) offer,
pledge, sell, contract to sell, sell any option or contract to purchase,
purchase any option or contract to sell, grant any option, right or warrant to
purchase, lend or otherwise transfer or dispose of, directly or indirectly, any
shares of the Common Stock or any securities convertible into or exercisable or
exchangeable for shares of the Common Stock (including, inter alia, the
Warrants) or (ii) enter into any swap or other arrangement that transfers to
another, in whole or in part, any of the economic consequences of ownership of
shares of the Common Stock, whether any such transaction described in clause (i)
or (ii) above is to be settled by delivery of shares of the Common Stock or
other securities, in cash or otherwise. The foregoing sentence shall not apply
to, or in any way affect, the Permitted Sales.

             (iii) The restrictions on trading activity set forth in this
Section H shall not apply to, and shall have no force and effect upon, the sale
or transfer of a Warrant, the Warrants or any part of a Warrant to any
third-party and such a purchaser, transferee or other recipient thereof shall
not be bound by the trading restrictions set forth in this Section H; provided,
however, that the trading restrictions set forth in this Section H shall survive
if such sale or transfer is to an affiliate of the Holder. For example, and for
the avoidance of any doubt, if the Holder sells the Warrants to an unaffiliated
third party, that unaffiliated third party may sell the Common Stock, long
and/or short, without any restriction as to volume (or otherwise) through any
means available in the public and/or private markets.

         I.  May 31, 2001 Omnibus Agreement. This Agreement supersedes and
replaces in its entirety the Omnibus Agreement between the Company and the
Holder, dated May 31, 2001.

         J.  Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of the State of New York applicable to agreements made
and to be performed within that State, without regard to the conflicts of laws
principles thereof.

         K.  Counterparts; Facsimile Signatures. This Agreement may be executed
in one or more counterparts, each of which shall be deemed an original, but all
of which when taken together shall constitute one and the same instrument. Any
copy of this Agreement containing a facsimile signature page shall be deemed an
original.

         L.  Whereas Clauses. The Whereas clause set forth in this Agreement are
hereby specifically made a part of this Agreement.

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BOSTON LIFE SCIENCES, INC.

/s/ David Hillson
--------------------------------
Name: David Hillson
Title: Chairman

BROWN SIMPSON PARTNERS I, LTD.

/s/ Peter D. Greene
--------------------------------
Peter D. Greene
Attorney-in-Fact

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                                   SCHEDULE I

   Warrant                                                         Number of
 Series/No.                     Registered Owner                    Shares
 ----------                     ----------------                    ------
     A/1                 Brown Simpson Partners I, Ltd.             835,749

     A/2                 Brown Simpson Partners I, Ltd.             208,937

     B/1                 Brown Simpson Partners I, Ltd.             620,350

     B/2                 Brown Simpson Partners I, Ltd.             155,087

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