EXHIBIT 4.1

                           HEMISPHERx BIOPHARMA, INC.
                          (FORMERLY HEM RESEARCH, INC.)
                              AMENDED AND RESTATED
                             1990 STOCK OPTION PLAN

1. Administration of Plan

This plan is intended to provide for the grant of stock options to persons whose
contributions  are  important  to  the  success  of  HEM  Research,   Inc.  (the
"Company").  This Plan shall be  administered  by the Board of  Directors of the
Company.  The Board of  Directors  is  authorized  to  interpret  the Plan,  the
prescribe,  amend and rescind rules and regulations  relating to it, and to make
all other  determinations  necessary or advisable  for its  administration.  The
Board of Directors may delegate to a committee  thereof any or all of its powers
and authority with respect to the administration of the Plan, and all references
herein to the Board of Directors shall be deemed to include any such committee.

2. Shares Covered by Plan

Options  may be  granted  under the plan  while  the Plan is in  effect  for the
purchase of not more than  460,798(1)  shares of the Common Stock,  $.001(1) par
value ("Common Stock"),  of the Company.  Shares covered by unexercised  options
that are no longer exercisable for any reason shall continue to be available for
issuance under options granted  hereunder for purposes of applying for foregoing
limitation.  Shares  delivered on exercise of options may be made available from
authorized and unissued stock or from stock held in the Treasury of the Company.

3. Eligibility

The Board of  Directors  may grant stock  options  under the Plan to  employees,
directors  and  officers of the Company and to  consultants,  advisors and other
persons  whose  contributions  are  important  to the  success  of the  Company,
provided that bonafide services shall be rendered by such consultants other than
in  connection  with the  offer  and  sale of  securities  in a  capital-raising
transaction.

4. Grant of Options

The  recipients of options  granted  under the Plan,  the number of shares to be
covered by each option, and the exercise price,  vesting terms, if any, duration
and  other  terms of each  option  (not  inconsistent  with the  Plan)  shall be
determined by the Board of Directors.




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5. Option Agreements

Each person to whom an option is granted  shall  enter into a written  agreement
with the Company setting forth the terms and conditions of the option granted to
him.

6. Duration of Options

No option  granted under the Plan shall be  exercisable  more than ten years and
one month from the date as of which the option agreement is executed.

7. Rights of a Stockholder

An optionee  shall have no rights as a  stockholder  with  respect to any shares
covered by his  options  until he shall have become the holder of record of such
shares, and no adjustment shall be made, except adjustments  pursuant to section
8 hereof, for dividends (ordinary or extraordinary  whether in cash,  securities
or other  property) or  distributions  or other rights in respect of such shares
for which the record date is prior to the date on which he shall have become the
holder of record thereof.

8. Effect of Change in Stock Subject to the Plan

If there is any change in the shares of Common Stock of the Company  through the
declaration of stock  dividends or through  recapitalization  resulting in stock
split-ups or  combinations  or exchanges of shares or  otherwise,  the number of
shares available for option, the exercise price of outstanding  options, and the
number of shares  subject to any option shall be  appropriately  adjusted by the
Board of Directors, and in their discretion,  in such cases, fractional parts of
shares may be disregarded.

9. Amendment and Discontinuance

The Board of  Directors  may from time to time alter or suspend  and at any time
discontinue the Plan.  However, no action of the Board of Directors may alter or
impair an optionee's  rights under any  outstanding  option  previously  granted
under the Plan without the consent of the holder of the option.

10. Termination Date

The Plan shall remain in effect until terminated by the Board of Directors.

Date: October 23, 1989




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Note (1): Plan amended to reflect  stock splits since 1990  consisting of a 10:1
Reverse Stock Split  effected in 1992, a 2.17015:1  Reverse Stock Split effected
on May 9, 1994 and a 2:1 Forward Stock Split on November 30, 1994. Also reflects
a change in par value to $.001 per share effective June 29, 1994.