Document:

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                                                                    EXHIBIT 10.4

                              AGREEMENT AND WAIVER

                                October 22, 2002

                  Reference is hereby made to that certain Purchase Agreement,
         dated as of December 5, 2000 (the "Purchase Agreement"), by and between
         Interleukin Genetics, Inc. (the "Company") and The Tail Wind Fund, Ltd.
         (the "Investor") and the Registration Rights Agreement, dated as of
         December 5, 2000, between the Company and the Investor (the
         "Registration Rights Agreement").

                  WHEREAS, pursuant to the Purchase Agreement, the Investor
         purchased and the Company issued and sold, (i) an aggregate of 800,000
         shares of the Company's common stock, $0.001 par value per share (the
         "Common Stock") at a purchase price of $2.50 per share and (ii) a
         warrant to purchase an aggregate of up to 264,407 additional shares of
         Common Stock at an exercise price of $3.15 per share (the "Warrant");

                  WHEREAS, the Company is negotiating a Strategic Transaction
         (as defined below) and in order to facilitate the consummation thereof,
         the Company and the Investor have agreed, among other things, that (i)
         the Company will issue Additional Registrable Securities to the
         Investor pursuant to Section 7.1 of the Purchase Agreement, (ii) the
         Investor will surrender the Warrant for cancellation, (iii) the
         Investor will waive certain rights under the Purchase Agreement and the
         Registration Rights Agreement and (iv) certain terms and conditions of
         the Purchase Agreement and the Registration Rights Agreement will be
         amended upon the consummation of the Strategic Transaction; and

                  WHEREAS, contemporaneous with the execution hereof the Company
         is entering into a Note Purchase Agreement (the "Note Purchase
         Agreement") with the Strategic Partner (as defined below) providing
         for, among other things, the Strategic Partner to advance up to
         $1,500,000 to the Company.

                  NOW, THEREFORE, in consideration for the mutual covenants
         contained herein and for other good and valuable consideration, the
         receipt and sufficiency of which are hereby acknowledged, the Company
         and the Investor hereby agree as follows:

                  1. The Investor hereby represents and warrants to the Company
         as a material inducement to the Company to enter into this Agreement
         that it continues to hold, in the aggregate, at least 65% of the shares
         of Common Stock originally issued to it pursuant to the Purchase
         Agreement. The Company hereby represents and warrants to the Investor
         that contemporaneous with the execution and delivery hereof, the
         Company is entering into an Agreement and Waiver with Special
         Situations Fund III, L.P., Special Situations Cayman Fund, L.P. and
         Special Situations Private Equity Fund, L.P. in the form presented to
         the Investor herewith (the "Other Investor Agreement").

                  2. Within five business days following the date hereof, the
         Investor shall surrender the Warrant to the Company for cancellation
         and exchange as set forth below. Within five business days following
         such surrender, the Company shall issue and deliver to the Investor an
         aggregate of 670,588 additional newly issued, fully paid and
         non-assessable shares of Common Stock (the "Additional Shares"), which
         Additional Shares shall be deemed to be issued pursuant to Section 7.1
         of the Purchase Agreement (such that an aggregate of 1,470,588 shares
         of

<PAGE>

         Common Stock shall have been issued under the Purchase Agreement and
         the effective Purchase Price for all such shares of Common Stock shall
         equal approximately $1.36). Such Additional Shares shall therefore be
         "Additional Registrable Securities" (as defined in the Registration
         Rights Agreement). Upon the delivery of certificates representing the
         Additional Shares to the Investor as provided herein, the Warrants
         shall terminate and no longer be outstanding. The Company hereby
         represents and warrants to the Investor that the Additional Shares have
         been duly authorized and, upon issuance pursuant to the terms of this
         Agreement, will be validly issued, fully paid and non-assessable and
         subject to no lien, claim, encumbrance or restriction whatsoever, other
         than restrictions arising pursuant to applicable securities laws.

         3. From the date hereof through April 1, 2003 (the "Waiver Termination
         Date"), the Investor hereby waives (i) any and all rights under Section
         7 of the Purchase Agreement and such section shall be of no force or
         effect with respect to any securities issued or deemed to be issued by
         the Company on or prior to the Waiver Termination Date, (ii) any and
         all rights under Section 2(c)(i)(C) of the Registration Rights
         Agreement and such section shall be of no further force or effect
         through the Waiver Termination Date, and (iii) any and all rights under
         Section 2(c)(i) of the Registration Rights Agreement to receive
         additional shares of Common Stock in payment of liquidated damages
         accruing through the Waiver Termination Date. Except as set forth in
         Section 5 hereof, the waiver set forth in this Section 3 shall be of no
         further force and effect from and after the Waiver Termination Date.

         4. In the event that the Company has not entered into a Strategic
         Transaction prior to the Waiver Termination Date, but has reached an
         agreement in principal with the Strategic Partner for a Strategic
         Transaction prior to such date, the Company shall provide the Investor
         with reasonably prompt notice thereof and the Waiver Termination Date
         shall be automatically extended to May 1, 2003 without any further
         action on the part of the parties hereto.

         5. In the event that the Company enters into a Strategic Transaction on
         or prior to the Waiver Termination Date, the Company shall provide the
         Investor with reasonably prompt notice thereof, and from and after the
         Waiver Termination Date, (i) Section 7 shall be deleted in its entirety
         from the Purchase Agreement, (ii) Section 2(c)(i)(C) shall be deleted
         in its entirety from the Registration Rights Agreement and (iii) in
         Section 2(c)(i) of the Registration Rights Agreement the phrase ", at
         the option of the Investor, in lawful money of the United States or in
         shares of Common Stock at the Market Price (as defined in the Purchase
         Agreement)," shall be replaced by the phrase " in lawful money of the
         United States".

         6. In the event that the Company has not entered into a Strategic
         Transaction on or prior to the Waiver Termination Date (as the same may
         be extended as provided in Section 4 above), within five business days
         thereafter the Company shall issue to the Investor a new warrants to
         purchase an aggregate of 264,407 shares of Common Stock at an exercise
         price of $1.70 per share and otherwise in substantially the same form
         as the Warrant (the "New Warrant"). The shares of Common Stock issuable
         upon exercise of the New Warrant shall be deemed to be "Additional
         Registrable Securities" under the Registration Rights Agreement. In the
         event that stockholder approval of the issuance of the New Warrant is
         then required under the rules and regulation of any stock exchange or
         stock market on which the Company's securities are then listed, quoted
         or admitted to trading, the Company shall use its best efforts to
         obtain such stockholder approval at the first annual meeting of
         stockholders held after the Waiver Termination Date and the New Warrant
         shall not be issued until such stockholder approval is obtained.

         7. For purposes of this Agreement, the term "Strategic Transaction"
         shall mean the sale and issuance by the Company to the Strategic
         Partner of the Company's equity or equity-

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         related securities resulting in gross proceeds to the Company on or
         prior to the Waiver Termination Date of at least Three Million Dollars
         ($3,000,000). For purposes of this Agreement, the term "Strategic
         Partner" shall mean the major Consumer Products company with whom the
         Company is contemporaneously herewith entering into the Note Purchase
         Agreement and its affiliates and related parties.

         8. Miscellaneous.

                  a. Notices. All notices, requests, consents and other
         communications hereunder shall be in writing, and given in accordance
         with Section 9.4 of the Purchase Agreement.

                  b. Governing Law. This Agreement and the rights and
         obligations of the parties hereunder shall be governed by and construed
         in accordance with the laws of New York, without giving effect to the
         conflict of law principles thereof.

                  c. Effect on Prior Agreements. Except as expressly modified as
         set forth herein, the Purchase Agreement and the Registration Rights
         Agreement shall remain in full force and effect.

                  d. Severability. If any court of competent jurisdiction
         determines any provision, or any portion thereof, of this Agreement to
         be unenforceable or invalid, then such provision shall be deemed
         limited to the extent that such court deems it valid or enforceable and
         the remaining provisions of this Agreement shall nevertheless remain in
         full force and effect.

                  e. Counterparts. This Agreement may be executed in any number
         of counterparts, and by different parties hereto on separate
         counterparts, each of which shall be deemed an original, but all of
         which together shall constitute one and the same instrument.

                  f. Expenses. Not later than one business day after the date
         hereof, the Company shall pay the reasonable legal fees and
         disbursements of counsel to the Investor incurred in connection with
         the negotiation and documentation of this Agreement; provided that such
         fees and disbursements shall in no event exceed $3,000.

                  g. Amendment. The Company agrees that it shall not amend or
         modify, or enter into any transaction which directly or indirectly
         amends or modifies, or has the effect of amending or modifying, the
         Other Investor Agreement unless the Investor is afforded equivalent
         treatment.

                  h. SEC Reporting. The Company shall prepare and file with the
         Securities and Exchange Commission a Current Report on Form 8-K (the
         "8-K") disclosing and attaching this Agreement within five business
         days of the date hereof. The Company represents and warrants to the
         Investor that it has not provided, and covenants that it will not
         provide, any non-public information to the Investor (except for the
         existence of this Agreement, the Other Investor Agreement and the Note
         Purchase Agreement, all of which will be disclosed in the 8-K).

         [THE REMAINDER OF THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK]

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                  IN WITNESS WHEREOF, the undersigned have executed this
         Agreement and Waiver as of the date first written above.

                                        INTERLEUKIN GENETICS, INC.

                                        By:      /s/ Fenel M. Eloi
                                                 -------------------------------
                                        Name:    Fenel M. Eloi
                                        Title:   Chief Financial Officer and
                                                 Chief Operating Officer

                                        THE TAIL WIND FUND, LTD.

                                        BY:      TAIL WIND ADVISORY AND
                                                 MANAGEMENT, LTD.
                                                 AS INVESTMENT MANAGER

                                        By:      /s/ David Crook
                                                 -------------------------------
                                        Name: David Crook
                                        Title: Chief Executive Officer<PAGE>
                                                                    EXHIBIT 10.5

                              AGREEMENT AND WAIVER

                                October 22, 2002

      Reference is hereby made to that certain Purchase Agreement, dated as of
January 26, 2001 (the "Purchase Agreement"), by and between Interleukin
Genetics, Inc. (the "Company"), Special Situations Fund III, L.P. ("SSF"),
Special Situations Cayman Fund, L.P. ("SSCF") and Special Situations Private
Equity Fund, L.P. ("SSPEF" and together with SSF and SSCF, the "Investors") and
the Registration Rights Agreement, dated as of January 26, 2001, between the
Company and the Investors (the "Registration Rights Agreement").

      WHEREAS, pursuant to the Purchase Agreement, the Investors purchased and
the Company issued and sold, (i) an aggregate of 1,200,000 shares of the
Company's common stock, $0.001 par value per share (the "Common Stock") at a
purchase price of $2.50 per share and (ii) warrants to purchase an aggregate of
up to 600,000 additional shares of Common Stock at an exercise price of $3.00
per share (the "Warrants");

      WHEREAS, the Company is negotiating a Strategic Transaction (as defined
below) and in order to facilitate the consummation thereof, the Company and the
Investors have agreed, among other things, that (i) the Company will issue
Additional Registrable Securities to the Investors pursuant to Section 7.1 of
the Purchase Agreement, (ii) the Investors will surrender the Warrants for
cancellation, (iii) the Investors will waive certain rights under the Purchase
Agreement and the Registration Rights Agreement and (iv) certain terms and
conditions of the Purchase Agreement and the Registration Rights Agreement will
be amended upon the consummation of the Strategic Transaction; and

      WHEREAS, contemporaneous with the execution hereof the Company is entering
into a Note Purchase Agreement (the "Note Purchase Agreement") with the
Strategic Partner (as defined below) providing for, among other things, the
Strategic Partner to advance up to $1,500,000 to the Company.

      NOW, THEREFORE, in consideration for the mutual covenants contained herein
and for other good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the Company and each Investor hereby agree as
follows:

      9. Each Investor hereby represents and warrants to the Company as a
material inducement to the Company to enter into this Agreement that it
continues to hold, in the aggregate, at least 65% of the shares of Common Stock
originally issued to it pursuant to the Purchase Agreement. The Company hereby
represents and warrants to each Investor that contemporaneous with the execution
and delivery hereof, the Company is entering into an Agreement and Waiver with
The Tail Wind Fund, Ltd. in the form presented to the Investors herewith (the
"Other Investor Agreement").

      10. Within five business days following the date hereof, the Investors
shall surrender the Warrants to the Company for cancellation and exchange as set
forth below. Within five business days following such surrender, the Company
shall issue and deliver to the Investors an aggregate of 1,005,670 additional
newly issued, fully paid and non-assessable shares of Common Stock (the
"Additional Shares"), which Additional Shares shall be deemed to be issued
pursuant to Section 7.1 of the Purchase Agreement (such that an aggregate of
2,205,670 shares of
<PAGE>
Common Stock shall have been issued under the Purchase Agreement and the
effective Purchase Price for all such shares of Common Stock shall equal
approximately $1.36). Such Additional Shares shall therefore be "Additional
Registrable Securities" (as defined in the Registration Rights Agreement) and
shall be issued pro rata to the Investors based upon the number of shares of
Common Stock each Investor originally purchased under the Purchase Agreement.
Upon the delivery of certificates representing the Additional Shares to the
Investors as provided herein, the Warrants shall terminate and no longer be
outstanding. The Company hereby represents and warrants to each Investor that
the Additional Shares have been duly authorized and, upon issuance pursuant to
the terms of this Agreement, will be validly issued, fully paid and
non-assessable and subject to no lien, claim, encumbrance or restriction
whatsoever, other than restrictions arising pursuant to applicable securities
laws.

      11. From the date hereof through April 1, 2003 (the "Waiver Termination
Date"), the Investors hereby waive (i) any and all rights under Section 7 of the
Purchase Agreement and such section shall be of no force or effect with respect
to any securities issued or deemed to be issued by the Company on or prior to
the Waiver Termination Date, (ii) any and all rights under Section 2(c)(i)(C) of
the Registration Rights Agreement and such section shall be of no further force
or effect through the Waiver Termination Date, and (iii) any and all rights
under Section 2(c)(i) of the Registration Rights Agreement to receive additional
shares of Common Stock in payment of liquidated damages accruing through the
Waiver Termination Date. Except as set forth in Section 5 hereof, the waiver set
forth in this Section 3 shall be of no further force and effect from and after
the Waiver Termination Date.

      12. In the event that the Company has not entered into a Strategic
Transaction prior to the Waiver Termination Date, but has reached an agreement
in principal with the Strategic Partner for a Strategic Transaction prior to
such date, the Company shall provide the Investors with reasonably prompt notice
thereof and the Waiver Termination Date shall be automatically extended to May
1, 2003 without any further action on the part of the parties hereto.

      13. In the event that the Company enters into a Strategic Transaction on
or prior to the Waiver Termination Date, the Company shall provide the Investors
with reasonably prompt notice thereof, and from and after the Waiver Termination
Date, (i) Section 7 shall be deleted in its entirety from the Purchase
Agreement, (ii) Section 2(c)(i)(C) shall be deleted in its entirety from the
Registration Rights Agreement and (iii) in Section 2(c)(i) of the Registration
Rights Agreement the phrase ", at the option of the Investors, in lawful money
of the United States or in shares of Common Stock at the Market Price (as
defined in the Purchase Agreement)," shall be replaced by the phrase " in lawful
money of the United States".

      14. In the event that the Company has not entered into a Strategic
Transaction on or prior to the Waiver Termination Date (as the same may be
extended as provided in Section 4 above), within five business days thereafter
the Company shall issue to the Investors new warrants to purchase an aggregate
of 600,000 shares of Common Stock at an exercise price of $1.70 per share and
otherwise in substantially the same form as the Warrants (the "New Warrants").
The shares of Common Stock issuable upon exercise of the New Warrants shall be
deemed to be "Additional Registrable Securities" under the Registration Rights
Agreement. In the event that stockholder approval of the issuance of the New
Warrants is then required under the rules and regulation of any stock exchange
or stock market on which the Company's securities are then listed, quoted or
admitted to trading, the Company shall use its best efforts to obtain such
stockholder approval at the first annual meeting of stockholders held after the
Waiver Termination Date and the New Warrants shall not be issued until such
stockholder approval is obtained.
<PAGE>
      15. For purposes of this Agreement, the term "Strategic Transaction" shall
mean the sale and issuance by the Company to the Strategic Partner of the
Company's equity or equity-related securities resulting in gross proceeds to the
Company on or prior to the Waiver Termination Date of at least Three Million
Dollars ($3,000,000). For purposes of this Agreement, the term "Strategic
Partner" shall mean the major Consumer Products company with whom the Company is
contemporaneously herewith entering into the Note Purchase Agreement and its
affiliates and related parties.

      16. Miscellaneous.

            a. Notices. All notices, requests, consents and other communications
hereunder shall be in writing, and given in accordance with Section 9.4 of the
Purchase Agreement.

            b. Governing Law. This Agreement and the rights and obligations of
the parties hereunder shall be governed by and construed in accordance with the
laws of New York, without giving effect to the conflict of law principles
thereof.

            c. Effect on Prior Agreements. Except as expressly modified as set
forth herein, the Purchase Agreement and the Registration Rights Agreement shall
remain in full force and effect.

            d. Severability. If any court of competent jurisdiction determines
any provision, or any portion thereof, of this Agreement to be unenforceable or
invalid, then such provision shall be deemed limited to the extent that such
court deems it valid or enforceable and the remaining provisions of this
Agreement shall nevertheless remain in full force and effect.

            e. Counterparts. This Agreement may be executed in any number of
counterparts, and by different parties hereto on separate counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

            f. Expenses. Not later than one business day after the date hereof,
the Company shall pay the reasonable legal fees and disbursements of counsel to
the Investors incurred in connection with the negotiation and documentation of
this Agreement; provided that such fees and disbursements shall in no event
exceed $3,000.

            g. Amendment. The Company agrees that it shall not amend or modify,
or enter into any transaction which directly or indirectly amends or modifies,
or has the effect of amending or modifying, the Other Investor Agreement unless
the Investor is afforded equivalent treatment.

            h. SEC Reporting. The Company shall prepare and file with the
Securities and Exchange Commission a Current Report on Form 8-K (the "8-K")
disclosing and attaching this Agreement within five business days of the date
hereof. The Company represents and warrants to the Investor that it has not
provided, and covenants that it will not provide, any non-public information to
the Investor (except for the existence of this Agreement, the Other Investor
Agreement and the Note Purchase Agreement, all of which will be disclosed in the
8-K).

         [THE REMAINDER OF THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK]
<PAGE>
      IN WITNESS WHEREOF, the undersigned have executed this Agreement and
Waiver as of the date first written above.

                                   INTERLEUKIN GENETICS, INC.

                                   By:      /s/ Fenel M. Eloi
                                       -----------------------------------------
                                   Name:    Fenel M. Eloi
                                   Title:   Chief Financial Officer and
                                            Chief Operating Officer

                                   SPECIAL SITUATIONS FUND III, L.P.

                                   By:      /s/ David Greenhouse
                                      ------------------------------------------
                                   Name: David Greenhouse
                                   Title: General Partner

                                   SPECIAL SITUATIONS CAYMAN FUND, L.P.

                                   By:      /s/ David Greenhouse
                                      ------------------------------------------
                                   Name: David Greenhouse
                                   Title: General Partner

                                   Special Situations Private Equity Fund, L.P.

                                   By:      /s/ David Greenhouse
                                      ------------------------------------------
                                   Name: David Greenhouse
                                   Title: General Partner

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