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                                                                    Exhibit 3(i)

                           CERTIFICATE OF DESIGNATIONS

                                       of

                  SERIES A JUNIOR PARTICIPATING PREFERRED STOCK

                                       of

                                   TANOX, INC.



             Pursuant to Section 151 of the General Corporation Law
                            of the State of Delaware

     TANOX, INC., a corporation organized and existing under the General
Corporation Law of the State of Delaware, in accordance with the provisions of
Section 103 thereof, DOES HEREBY CERTIFY:

     That pursuant to the authority vested in the Board of Directors in
accordance with the provisions of the Amended and Restated Certificate of
Incorporation of the said Corporation, the said Board of Directors on July 27,
2001 adopted the following resolution creating a series of 1,200,000 shares of
Preferred Stock designated as "Series A Junior Participating Preferred Stock":

     RESOLVED, that pursuant to the authority vested in the Board of Directors
of this Corporation in accordance with the provisions of the Amended and
Restated Certificate of Incorporation, a series of Preferred Stock, par value
$.01 per share, of the Corporation be and hereby is created, and that the
designation and number of shares thereof and the voting and other powers,
preferences and relative, participating, optional or other rights of the shares
of such series and the qualifications, limitations and restrictions thereof are
as follows:

                  Series A Junior Participating Preferred Stock

     1. Designation and Amount. There shall be a series of Preferred Stock that
shall be designated as "Series A Junior Participating Preferred Stock," and the
number of shares constituting such series shall be 1,200,000. Such number of
shares may be increased or decreased by resolution of the Board of Directors;
provided, however, that no decrease shall reduce the number of shares of Series
A Junior Participating Preferred Stock to less than the number of shares then
issued and outstanding plus the number of shares issuable upon exercise of
outstanding rights, options or warrants or upon conversion of outstanding
securities issued by the Corporation.

     2. Dividends and Distributions.

     (A) Subject to the prior and superior rights of the holders of any shares
of any series of Preferred Stock ranking prior and superior to the shares of
Series A Junior Participating Preferred Stock with respect to dividends, the
holders of shares of Series A Junior Participating Preferred Stock, in
preference to the holders of shares of any class or series of stock of the

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Corporation ranking junior to the Series A Junior Participating Preferred Stock,
shall be entitled to receive, when, as and if declared by the Board of Directors
out of funds legally available for the purpose, quarterly dividends payable in
cash on the last day of March, June, September and December in each year (each
such date being referred to herein as a "Quarterly Dividend Payment Date"),
commencing on the first Quarterly Dividend Payment Date after the first issuance
of a share or fraction of a share of Series A Junior Participating Preferred
Stock, in an amount per share (rounded to the nearest cent) equal to the greater
of (a) $1.00 or (b) the Adjustment Number (as defined below) times the aggregate
per share amount of all cash dividends, and the Adjustment Number times the
aggregate per share amount (payable in kind) of all non-cash dividends or other
distributions other than a dividend payable in shares of Common Stock or a
subdivision of the outstanding shares of Common Stock (by reclassification or
otherwise), declared on the Common Stock, par value $.01 per share, of the
Corporation (the "Common Stock") since the immediately preceding Quarterly
Dividend Payment Date, or, with respect to the first Quarterly Dividend Payment
Date, since the first issuance of any share or fraction of a share of Series A
Junior Participating Preferred Stock. The "Adjustment Number" shall initially be
100. In the event the Corporation shall at any time after July 27, 2001 (the
"Rights Declaration Date") (i) declare any dividend on Common Stock payable in
shares of Common Stock, (ii) subdivide the outstanding Common Stock or (iii)
combine the outstanding Common Stock into a smaller number of shares, then in
each such case the Adjustment Number in effect immediately prior to such event
shall be adjusted by multiplying such Adjustment Number by a fraction the
numerator of which is the number of shares of Common Stock outstanding
immediately after such event and the denominator of which is the number of
shares of Common Stock that were outstanding immediately prior to such event.

     (B) The Corporation shall declare a dividend or distribution on the Series
A Junior Participating Preferred Stock as provided in paragraph (A) above
immediately after it declares a dividend or distribution on the Common Stock
(other than a dividend payable in shares of Common Stock); provided that, in the
event no dividend or distribution shall have been declared on the Common Stock
during the period between any Quarterly Dividend Payment Date and the next
subsequent Quarterly Dividend Payment Date, a dividend of $1.00 per share on the
Series A Junior Participating Preferred Stock shall nevertheless be payable on
such subsequent Quarterly Dividend Payment Date.

     (C) Dividends shall begin to accrue and be cumulative on outstanding shares
of Series A Junior Participating Preferred Stock from the Quarterly Dividend
Payment Date next preceding the date of issue of such shares of Series A Junior
Participating Preferred Stock, unless the date of issue of such shares is prior
to the record date for the first Quarterly Dividend Payment Date, in which case
dividends on such shares shall begin to accrue from the date of issue of such
shares, or unless the date of issue is a Quarterly Dividend Payment Date or is a
date after the record date for the determination of holders of shares of Series
A Junior Participating Preferred Stock entitled to receive a quarterly dividend
and before such Quarterly Dividend Payment Date, in either of which events such
dividends shall begin to accrue and be cumulative from such Quarterly Dividend
Payment Date. Accrued but unpaid dividends shall not bear interest. Dividends
paid on the shares of Series A Junior Participating Preferred Stock in an amount
less than the total amount of such dividends at the time accrued and payable on
such shares shall be allocated pro rata on a share-by-share basis among all such
shares at the time outstanding. The Board of Directors may fix a record date for
the determination of holders of


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shares of Series A Junior Participating Preferred Stock entitled to receive
payment of a dividend or distribution declared thereon, which record date shall
be no more than 30 days prior to the date fixed for the payment thereof.

     3. Voting Rights. The holders of shares of Series A Junior Participating
Preferred Stock shall have the following voting rights:

     (A) Each share of Series A Junior Participating Preferred Stock shall
entitle the holder thereof to a number of votes equal to the Adjustment Number
on all matters submitted to a vote of the stockholders of the Corporation.

     (B) Except as otherwise provided herein, in the Amended and Restated
Certificate of Incorporation or by law, the holders of shares of Series A Junior
Participating Preferred Stock, the holders of shares of any other class or
series entitled to vote with the Common Stock and the holders of shares of
Common Stock shall vote together as one class on all matters submitted to a vote
of stockholders of the Corporation.

     (C) (i) If at any time dividends on any Series A Junior Participating
Preferred Stock shall be in arrears in an amount equal to six quarterly
dividends thereon, the occurrence of such contingency shall mark the beginning
of a period (herein called a "default period") that shall extend until such time
when all accrued and unpaid dividends for all previous quarterly dividend
periods and for the current quarterly dividend period on all shares of Series A
Junior Participating Preferred Stock then outstanding shall have been declared
and paid or set apart for payment. During each default period, (1) the number of
Directors shall be increased by two, effective as of the time of election of
such Directors as herein provided, and (2) the holders of Preferred Stock
(including holders of the Series A Junior Participating Preferred Stock) upon
which these or like voting rights have been conferred and are exercisable (the
"Voting Preferred Stock") with dividends in arrears in an amount equal to six
quarterly dividends thereon, voting as a class, irrespective of series, shall
have the right to elect such two Directors.

     (ii) During any default period, such voting right of the holders of Series
A Junior Participating Preferred Stock may be exercised initially at a special
meeting called pursuant to subparagraph (iii) of this Section 3(C) or at any
annual meeting of stockholders, and thereafter at annual meetings of
stockholders, provided that such voting right shall not be exercised unless the
holders of at least one-third in number of the shares of Voting Preferred Stock
outstanding shall be present in person or by proxy. The absence of a quorum of
the holders of Common Stock shall not affect the exercise by the holders of
Voting Preferred Stock of such voting right. At any meeting at which the holders
of Voting Preferred Stock shall exercise such voting right initially during an
existing default period, they shall have the right, voting as a class, to elect
two Directors. After the holders of the Voting Preferred Stock shall have
exercised their right to elect Directors in any default period and during the
continuance of such period, the number of Directors shall not be increased or
decreased except by vote of the holders of Voting Preferred Stock as herein
provided or pursuant to the rights of any equity securities ranking senior to or
pari passu with the Series A Junior Participating Preferred Stock.

     (iii) Unless the holders of Voting Preferred Stock shall, during an
existing default period, have previously exercised their right to elect
Directors, the Board of Directors


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may order, or any stockholder or stockholders owning in the aggregate not less
than ten percent of the total number of shares of Voting Preferred Stock
outstanding, irrespective of series, may request, the calling of a special
meeting of the holders of Voting Preferred Stock, which meeting shall thereupon
be called by the Chairman of the Board, the President, a Vice President or the
Secretary of the Corporation. Notice of such meeting and of any annual meeting
at which holders of Voting Preferred Stock are entitled to vote pursuant to this
paragraph (C)(iii) shall be given to each holder of record of Voting Preferred
Stock by mailing a copy of such notice to him at his last address as the same
appears on the books of the Corporation. Such meeting shall be called for a time
not earlier than 20 days and not later than 60 days after such order or request
or, in default of the calling of such meeting within 60 days after such order or
request, such meeting may be called on similar notice by any stockholder or
stockholders owning in the aggregate not less than ten percent of the total
number of shares of Voting Preferred Stock outstanding. Notwithstanding the
provisions of this paragraph (C)(iii), no such special meeting shall be called
during the period within 60 days immediately preceding the date fixed for the
next annual meeting of the stockholders.

     (iv) In any default period, after the holders of Voting Preferred Stock
shall have exercised their right to elect Directors voting as a class, (x) the
Directors so elected by the holders of Voting Preferred Stock shall continue in
office until their successors shall have been elected by such holders or until
the expiration of the default period, and (y) any vacancy in the Board of
Directors may (except as provided in paragraph (C)(ii) of this Section 3) be
filled by vote of a majority of the remaining Directors theretofore elected by
the holders of the class or classes of stock which elected the Director whose
office shall have become vacant. References in this paragraph (C) to Directors
elected by the holders of a particular class or classes of stock shall include
Directors elected by such Directors to fill vacancies as provided in clause (y)
of the foregoing sentence.

     (v) Immediately upon the expiration of a default period, (x) the right of
the holders of Voting Preferred Stock as a class to elect Directors shall cease,
(y) the term of any Directors elected by the holders of Voting Preferred Stock
as a class shall terminate and (z) the number of Directors shall be such number
as may be provided for in the Amended and Restated Certificate of Incorporation
or By-Laws irrespective of any increase made pursuant to the provisions of
paragraph (C) of this Section 3 (such number being subject, however, to change
thereafter in any manner provided by law or in the Amended and Restated
Certificate of Incorporation or By-Laws). Any vacancies in the Board of
Directors effected by the provisions of clauses (y) and (z) in the preceding
sentence may be filled by a majority of the remaining Directors.

     (D) Except as set forth herein, holders of Series A Junior Participating
Preferred Stock shall have no special voting rights and their consent shall not
be required (except to the extent they are entitled to vote with holders of
Common Stock as set forth herein) for taking any corporate action.

     4. Certain Restrictions.

     (A) Whenever quarterly dividends or other dividends or distributions
payable on the Series A Junior Participating Preferred Stock as provided in
Section 2 are in arrears,


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thereafter and until all accrued and unpaid dividends and distributions, whether
or not declared, on shares of Series A Junior Participating Preferred Stock
outstanding shall have been paid in full, the Corporation shall not

          (i) declare or pay dividends on, make any other distributions on, or
     redeem or purchase or otherwise acquire for consideration any shares of
     stock ranking junior (either as to dividends or upon liquidation,
     dissolution or winding up) to the Series A Junior Participating Preferred
     Stock;

          (ii) declare or pay dividends on or make any other distributions on
     any shares of stock ranking on a parity (either as to dividends or upon
     liquidation, dissolution or winding up) with the Series A Junior
     Participating Preferred Stock, except dividends paid ratably on the Series
     A Junior Participating Preferred Stock and all such parity stock on which
     dividends are payable or in arrears in proportion to the total amounts to
     which the holders of all such shares are then entitled; or

          (iii) redeem or purchase or otherwise acquire for consideration any
     shares of Series A Junior Participating Preferred Stock, or any shares of
     stock ranking on a parity with the Series A Junior Participating Preferred
     Stock, except in accordance with a purchase offer made in writing or by
     publication (as determined by the Board of Directors) to all holders of
     Series A Junior Participating Preferred Stock, or to all such holders and
     the holders of any such shares ranking on a parity therewith, upon such
     terms as the Board of Directors, after consideration of the respective
     annual dividend rates and other relative rights and preferences of the
     respective series and classes, shall determine in good faith will result in
     fair and equitable treatment among the respective series or classes.

     (B) The Corporation shall not permit any subsidiary of the Corporation to
purchase or otherwise acquire for consideration any shares of stock of the
Corporation unless the Corporation could, under paragraph (A) of this Section 4,
purchase or otherwise acquire such shares at such time and in such manner.

     5. Reacquired Shares. Any shares of Series A Junior Participating Preferred
Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall be retired and canceled promptly after the acquisition thereof.
All such shares shall upon their cancellation become authorized but unissued
shares of Preferred Stock and may be reissued as part of a new series of
Preferred Stock to be created by resolution or resolutions of the Board of
Directors, subject to any conditions and restrictions on issuance set forth
herein.

     6. Liquidation, Dissolution or Winding Up. (A) Upon any liquidation
(voluntary or otherwise), dissolution or winding up of the Corporation, no
distribution shall be made to the holders of shares of stock ranking junior
(either as to dividends or upon liquidation, dissolution or winding up) to the
Series A Junior Participating Preferred Stock unless, prior thereto, the holders
of shares of Series A Junior Participating Preferred Stock shall have received
$100 per share, plus an amount equal to accrued and unpaid dividends and
distributions thereon, whether or not declared, to the date of such payment (the
"Series A Junior Participating Preferred Stock Liquidation Preference").
Following the payment of the full amount of the Series A Junior


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Participating Preferred Stock Liquidation Preference, no additional
distributions shall be made to the holders of shares of Series A Junior
Participating Preferred Stock unless, prior thereto, the holders of shares of
Common Stock shall have received an amount per share (the "Common Adjustment")
equal to the quotient obtained by dividing (i) the Series A Junior Participating
Preferred Stock Liquidation Preference by (ii) the Adjustment Number. Following
the payment of the full amount of the Series A Junior Participating Preferred
Stock Liquidation Preference and the Common Adjustment in respect of all
outstanding shares of Series A Junior Participating Preferred Stock and Common
Stock, respectively, holders of Series A Junior Participating Preferred Stock
and holders of shares of Common Stock shall, subject to the prior rights of all
other series of Preferred Stock, if any, ranking prior thereto, receive their
ratable and proportionate share of the remaining assets to be distributed in the
ratio of the Adjustment Number to 1 with respect to such Series A Junior
Participating Preferred Stock and Common Stock, on a per share basis,
respectively.

     (B) In the event, however, that there are not sufficient assets available
to permit payment in full of the Series A Junior Participating Preferred Stock
Liquidation Preference and the liquidation preferences of all other series of
Preferred Stock, if any, that rank on a parity with the Series A Junior
Participating Preferred Stock, then such remaining assets shall be distributed
ratably to the holders of such parity shares in proportion to their respective
liquidation preferences. In the event, however, that there are not sufficient
assets available to permit payment in full of the Common Adjustment, then such
remaining assets shall be distributed ratably to the holders of Common Stock.

     (C) Neither the merger or consolidation of the Corporation into or with
another corporation nor the merger or consolidation of any other corporation
into or with the Corporation shall be deemed to be a liquidation, dissolution or
winding up of the Corporation within the meaning of this Section 6, but the
sale, lease or conveyance of all or substantially all the Corporation's assets
shall be deemed to be a liquidation, dissolution or winding up of the
Corporation within the meaning of this Section 6.

     7. Consolidation, Merger, etc. In case the Corporation shall enter into any
consolidation, merger, combination or other transaction in which the shares of
Common Stock are exchanged for or changed into other stock or securities, cash
and/or any other property, then in any such case each share of Series A Junior
Participating Preferred Stock shall at the same time be similarly exchanged or
changed in an amount per share equal to the Adjustment Number times the
aggregate amount of stock, securities, cash and/or any other property (payable
in kind), as the case may be, into which or for which each share of Common Stock
is changed or exchanged.

     8. Redemption. (A) The Corporation, at its option, may redeem shares of the
Series A Junior Participating Preferred Stock in whole at any time and in part
from time to time, at a redemption price equal to the Adjustment Number times
the current per share market price (as such term is hereinafter defined) of the
Common Stock on the date of the mailing of the notice of redemption, together
with unpaid accumulated dividends to the date of such redemption. The "current
per share market price" on any date shall be deemed to be the average of the
closing price per share of such Common Stock for the ten consecutive Trading
Days (as such term is hereinafter defined) immediately prior to such date;
provided, however, that in the


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event that the current per share market price of the Common Stock is determined
during a period following the announcement of (A) a dividend or distribution on
the Common Stock other than a regular quarterly cash dividend or (B) any
subdivision, combination or reclassification of such Common Stock and the
ex-dividend date for such dividend or distribution, or the record date for such
subdivision, combination or reclassification, shall not have occurred prior to
the commencement of such ten Trading Day period, then, and in each such case,
the current per share market price shall be properly adjusted to take into
account ex-dividend trading. The closing price for each day shall be the last
sales price, regular way, or, in case no such sale takes place on such day, the
average of the closing bid and asked prices, regular way, in either case as
reported in the principal transaction reporting system with respect to
securities listed or admitted to trading on the New York Stock Exchange, or, if
the Common Stock is not listed or admitted to trading on the New York Stock
Exchange, on the principal national securities exchange on which the Common
Stock is listed or admitted to trading, or, if the Common Stock is not listed or
admitted to trading on any national securities exchange but sales price
information is reported for such security, as reported by the National
Association of Securities Dealers, Inc. Automated Quotations System ("NASDAQ")
or such other self-regulatory organization or registered securities information
processor (as such terms are used under the Securities Exchange Act of 1934, as
amended) that then reports information concerning the Common Stock, or, if sales
price information is not so reported, the average of the high bid and low asked
prices in the over-the-counter market on such day, as reported by NASDAQ or such
other entity, or, if on any such date the Common Stock is not quoted by any such
entity, the average of the closing bid and asked prices as furnished by a
professional market maker making a market in the Common Stock selected by the
Board of Directors of the Corporation. If on any such date no such market maker
is making a market in the Common Stock, the fair value of the Common Stock on
such date as determined in good faith by the Board of Directors of the
Corporation shall be used. The term "Trading Day" shall mean a day on which the
principal national securities exchange on which the Common Stock is listed or
admitted to trading is open for the transaction of business, or, if the Common
Stock is not listed or admitted to trading on any national securities exchange
but is quoted by NASDAQ, a day on which NASDAQ reports trades, or, if the Common
Stock is not so quoted, a Monday, Tuesday, Wednesday, Thursday or Friday on
which banking institutions in the State of New York are not authorized or
obligated by law or executive order to close.

     (B) In the event that fewer than all the outstanding shares of the Series A
Junior Participating Preferred Stock are to be redeemed, the number of shares to
be redeemed shall be determined by the Board of Directors and the shares to be
redeemed shall be determined by lot or pro rata as may be determined by the
Board of Directors or by any other method that may be determined by the Board of
Directors in its sole discretion to be equitable.

     (C) Notice of any such redemption shall be given by mailing to the holders
of the shares of Series A Junior Participating Preferred Stock to be redeemed a
notice of such redemption, first class postage prepaid, not later than the
fifteenth day and not earlier than the sixtieth day before the date fixed for
redemption, at their last address as the same shall appear upon the books of the
Corporation. Each such notice shall state: (i) the redemption date; (ii) the
number of shares to be redeemed and, if fewer than all the shares held by such
holder are to be redeemed, the number of such shares to be redeemed from such
holder; (iii) the redemption price; (iv) the place or places where certificates
for such shares are to be surrendered for payment of the redemption price; and
(v) that dividends on the shares to be redeemed will cease to accrue


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on the close of business on such redemption date. Any notice that is mailed in
the manner herein provided shall be conclusively presumed to have been duly
given, whether or not the stockholder received such notice, and failure duly to
give such notice by mail, or any defect in such notice, to any holder of Series
A Junior Participating Preferred Stock shall not affect the validity of the
proceedings for the redemption of any other shares of Series A Junior
Participating Preferred Stock that are to be redeemed. On or after the date
fixed for redemption as stated in such notice, each holder of the shares called
for redemption shall surrender the certificate evidencing such shares to the
Corporation at the place designated in such notice and shall thereupon be
entitled to receive payment of the redemption price. If fewer than all the
shares represented by any such surrendered certificate are redeemed, a new
certificate shall be issued representing the unredeemed shares.

     (D) The shares of Series A Junior Participating Preferred Stock shall not
be subject to the operation of any purchase, retirement or sinking fund.

     9. Ranking. The Series A Junior Participating Preferred Stock shall rank
junior to all other series of the Corporation's Preferred Stock as to the
payment of dividends and the distribution of assets, unless the terms of any
such series shall provide otherwise, and shall rank senior to the Common Stock
as to such matters.

     10. Amendment. At any time that any shares of Series A Junior Participating
Preferred Stock are outstanding, the Amended and Restated Certificate of
Incorporation of the Corporation shall not be amended in any manner which would
materially alter or change the powers, preferences or special rights of the
Series A Junior Participating Preferred Stock so as to affect them adversely
without the affirmative vote of the holders of two-thirds or more of the
outstanding shares of Series A Junior Participating Preferred Stock, voting
separately as a class.

     11. Fractional Shares. Series A Junior Participating Preferred Stock may be
issued in fractions of a share that shall entitle the holder, in proportion to
such holder's fractional shares, to exercise voting rights, receive dividends,
participate in distributions and to have the benefit of all other rights of
holders of Series A Junior Participating Preferred Stock.

     IN WITNESS WHEREOF, the undersigned has executed this Certificate and does
affirm the foregoing as true this 18th day of June 2002.



                                   /s/ Katie-Pat Bowman
                                   ---------------------------------------------
                                   Katie-Pat Bowman
                                   Vice President, General Counsel and Secretary

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