Filed by Sanofi-Synthelabo
                                            Pursuant to Rule 165 and Rule 425(a)
                      under the United States Securities Act of 1933, as amended

                                                        Subject Company: Aventis
                                                   Commission File No. 001-10378
                                                              Date: May 26, 2004


         On May 26, 2004, Sanofi-Synthelabo issued the following two press
releases.

         In connection with the proposed acquisition of Aventis,
Sanofi-Synthelabo has filed with the United States Securities and Exchange
Commission (SEC), a registration statement on Form F-4 (File no: 333-112314),
which includes a prospectus/offer to exchange and related exchange offer
materials, to register the Sanofi-Synthelabo ordinary shares (including
Sanofi-Synthelabo ordinary shares represented by Sanofi-Synthelabo ADSs) to be
issued in exchange for Aventis ordinary shares held by holders located in the
United States and for Aventis ADSs held by holders wherever located and has also
filed with the SEC a Statement on Schedule TO. INVESTORS AND HOLDERS OF AVENTIS
SECURITIES ARE STRONGLY ADVISED TO READ THE REGISTRATION STATEMENT AND THE
PROSPECTUS/OFFER TO EXCHANGE, THE RELATED EXCHANGE OFFER MATERIALS AND THE
STATEMENT ON SCHEDULE TO, AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC,
AS WELL AS ANY AMENDMENTS AND SUPPLEMENTS (INCLUDING ANY SUPPLEMENT RELATING TO
SANOFI-SYNTHELABO'S REVISED OFFER), BECAUSE THEY CONTAIN IMPORTANT INFORMATION.
Investors and holders of Aventis securities may obtain free copies of the
registration statement, the prospectus/offer to exchange and related exchange
offer materials, and the Statement on Schedule TO, as well as other relevant
documents filed with the SEC, at the SEC's web site at www.sec.gov. The
prospectus/offer to exchange and other transaction-related documents are being
mailed to Aventis securityholders eligible to participate in the U.S. offer and
additional copies may be obtained for free from MacKenzie Partners, Inc., the
information agent for the U.S. offer, at the following address: 105, Madison
Avenue, New York, New York 10016; telephone 1-(212) 929-5500 (call collect) or
1-(800) 322-2885 (toll-free call); e-mail proxy@mackenziepartners.com. In
connection with its revised offer, Sanofi-Synthelabo intends to distribute a
supplement to the prospectus/offer to exchange as soon as practicable.


                                     * * * *





                                                               Sanofi-Synthelabo


 Investor Relations

                                                             Paris, May 26, 2004


                GENERAL MEETING OF SANOFI-SYNTHELABO SHAREHOLDERS
                      SANOFI-SYNTHELABO'S OFFER FOR AVENTIS

The Board of Directors of Sanofi-Synthelabo, at its meeting of May 24, 2004,
finalized the list of directors whose nomination will be proposed to the General
Meeting of Sanofi-Synthelabo shareholders to be held on June 23, 2004.

In accordance with the agreement, dated April 25, 2004, between Aventis and
Sanofi-Synthelabo, it is proposed that Sanofi-Synthelabo's Board of Directors
will be composed as follows:

        o        Jean-Francois Dehecq and

        o        8 directors proposed by the Board of Directors of
                 Sanofi-Synthelabo:
                        o   Rene Barbier de la Serre
                        o   Robert Castaigne
                        o   Thierry Desmarest
                        o   Lord Douro
                        o   Christian Mulliez
                        o   Lindsay Owen-Jones
                        o   Gerard Van Kemmel
                        o   Bruno Weymuller

         whose terms of office would take effect at the end of the General
         Meeting of shareholders, and:

        o        8 directors proposed by the Supervisory Board of Aventis:

                        o   Jean-Marc Bruel
                        o   Jurgen Dormann
                        o   Jean-Rene Fourtou
                        o   Serge Kampf
                        o   Igor Landau
                        o   Hubert Markl
                        o   Klaus Pohle
                        o   Hermann Scholl


    subject to the successful settlement of the offers in France, in the United
    States and in Germany.

In addition, in connection with Sanofi-Synthelabo's offer for Aventis,
Sanofi-Synthelabo announces:

        o        the successful completion of the first round of syndication of
                 the 16 billion euro credit facility put in place in connection
                 with its revised offer for Aventis with the same syndicate of
                 banks as for the initial offer; that is, in addition to BNP
                 Paribas and Merrill Lynch, as Mandated Lead Arrangers:



                        o   ABN AMRO Bank
                        o   Banco Bilbao Vizcaya Argentaria
                        o   The Bank of Tokyo-Mitsubishi
                        o   CDC Finance- CDC IXIS
                        o   Natexis Banques Populaires
                        o   The Royal Bank of Scotland
                        o   WestLB AG

        o        The agreement of Sanofi-Synthelabo and Aventis, on May 19,
                 2004, to amend to their Agreement, dated April 25, 2004, to
                 revise the provisions relating to the liquidity arrangements
                 provided for the benefit of the holders of Aventis stock
                 purchase and stock subscription options (a copy of the
                 amendment is attached to this press release).


In accordance with article 7 of the COB rule no. 2002-04, this press release was
transmitted to the Autorite des marches financiers (AMF) before its publication.

IMPORTANT INFORMATION: In connection with the proposed acquisition of Aventis,
Sanofi-Synthelabo has filed a registration statement on Form F-4 (File no.
333-112314), including a prospectus/offer to exchange, and will file additional
documents with the SEC. INVESTORS ARE URGED TO READ THE REGISTRATION STATEMENT,
INCLUDING THE PROSPECTUS/OFFER TO EXCHANGE, AND ANY OTHER RELEVANT DOCUMENTS
FILED WITH THE SEC, INCLUDING ALL AMENDMENTS AND SUPPLEMENTS (INCLUDING ANY
SUPPLEMENT RELATING TO ITS REVISED OFFERS), BECAUSE THEY CONTAIN IMPORTANT
INFORMATION. Free copies of the registration statement, as well as other
relevant documents filed with the SEC, may be obtained at the SEC's web site at
www.sec.gov. The prospectus/offer to exchange and other transaction-related
documents are being mailed to Aventis securityholders eligible to participate in
the U.S. offer and additional copies may be obtained for free from MacKenzie
Partners, Inc., the information agent for the U.S. offer, at the following
address: 105, Madison Avenue, New York, New York 10016; telephone: 1-(212)
929-5500 (call collect) or 1-(800) 322-2885 (toll-free call); e-mail
proxy@mackenziepartners.com. In connection with its revised offer,
Sanofi-Synthelabo intends to distribute a supplement to the prospectus/offer to
exchange in the coming days.

In France, holders of Aventis securities are requested, with respect to the
offer, to refer to the prospectus supplement (note d'information
complementaire), which has been granted visa number 04-384 by the Autorite des
marches financiers ("AMF") and which is available on the website of the AMF
(www.amf-france.org) and without cost from: BNP Paribas Securities Services,
GIS-Emetteurs, Service Logistique, Les Collines de l'Arche, 75450 Paris Cedex 9
and to the recommendation statement (note d'information en reponse) of Aventis
when it is available.

The public offer to holders of Aventis ordinary shares located in Germany (the
"German Offer") is being made in accordance with applicable German law and
pursuant to an offer document/sales prospectus, which is available free of
charge at BNP Paribas Securities Services, Gruneburgweg 14, D-60322 Frankfurt am
Main (Fax: 069 - 152 05 277) and on the website of the Company
(www.sanofi-synthelabo.com). Any decision to tender Aventis ordinary shares in
exchange for Sanofi-Synthelabo ordinary shares under the German Offer must be
taken exclusively with regard to the terms and conditions of the German Offer,
as well as with regard to the information included in the offer document/sales
prospectus, including any amendments thereto, issued in Germany.

The French Offer, the U.S. Offer and the German Offer are being made on
substantially the same terms and completion of these offers is subject to the
same conditions. It is intended that the three offers will expire at the same
time.

Investors and security holders may obtain a free copy of the Form 20-F filed
with the SEC on April 2, 2004 and any other documents filed by Sanofi-Synthelabo
with the SEC at www.sec.gov as well as of the Reference Document filed with the
AMF on April 2, 2004 (N(degree) 04-0391) at www.amf-france.org or directly from
Sanofi-Synthelabo on our web site at: www.sanofi-synthelabo.com.

INVESTOR RELATIONS DEPARTMENT
Philippe Goupit         Director of Investor Relations
Arnaud Delepine         Investor Relations Europe
Sanjay Gupta            Investor Relations US
Anne d'Halluin-Sulzer   Investor Relations

CONTACTS:
E-mail: investor-relations@sanofi-synthelabo.com
Europe                          US
Tel: +33 1 53 77 45 45          Tel: +1 212 551 42 93
Fax: +33 1 53 77 42 96          Fax: +1 212 551 49 92

                                                                             2/4


                                                                          Annexe



                                   SCHEDULE 1
                       LIQUIDITY FOR AVENTIS STOCK-OPTIONS

The liquidity mechanism described below shall be offered by Sanofi-Synthelabo in
the form of a joint letter with Aventis to be dispatched by mail within 30 days
of the publication of the results of the French Offer. This offer of liquidity
mechanism will remain open for acceptance until 31 March 2005.

The objective of this liquidity mechanism is to enable the Aventis, RPR or
Hoechst stock option holders not to be affected by the Offers and to benefit
from its terms once the stock options will be exercised without undue cost to
the holders, Sanofi-Synthelabo and Aventis, RPR or Hoechst.

For the avoidance of doubt, if (i) any particular situation would not be
properly covered by the following liquidity mechanism or (ii) the enforcement of
any provision of this mechanism turns out to be impossible or significantly
detrimental to the stock-option holders, to Aventis or to Sanofi-Synthelabo with
regard to securities or company or tax laws, a specific alternative solution
will be fairly determined between Aventis and Sanofi-Synthelabo

Sanofi-Synthelabo will offer all Aventis, RPR or Hoechst Stock Option holders a
liquidity agreement, the main terms and conditions of which will be the
following (such terms and conditions to be detailed in good faith in the
liquidity agreement):

                o Undertaking by Sanofi-Synthelabo to exchange the Aventis
                  shares purchased or subscribed for pursuant to the exercise of
                  Stock Options, whether before or after the close of the Offer,
                  under the following terms:

                  (i)    the exchange of shares shall take place only in the
                         case where (x) the Aventis shares are no longer listed
                         on the Euronext Paris or Frankfurt or New York Stock
                         Exchange, (y) Sanofi-Synthelabo owns more than 90% of
                         Aventis outstanding ordinary shares or (z) the average
                         daily volume of Aventis shares traded on Euronext Paris
                         during any twenty trading day period is less than
                         1,000,000 shares;

                  (ii)   the exchange of shares shall take place (a) at the
                         holder's request, at any time during the "Liquidity
                         Period". The Liquidity Period shall be the period
                         during which the holder is entitled to exercise his
                         Options under the terms of the relevant options scheme,
                         but starting, as the case may be, at the end of the
                         period when the exercise of the liquidity agreement
                         will not create any negative tax or social charges for
                         a company of the Sanofi Synthelabo group (the
                         "Restricted  Period"), plus any additional waiting
                         period required by law to get the full tax benefit (1)
                         (such Liquidity Period being adjusted, for Option
                         Shares funded from employees saving plans (PEE),
                         as corresponding to a period of six month following
                         the expiry of the specific tax and social security
                         holding period applicable to PEE) or (b) at the latest,
                         by the expiry of the Liquidity Period;

                  (iii)  the exchange ratio of Aventis shares to Sanofi-
                         Synthelabo shares will be 1.1739 Sanofi-Synthelabo
                         shares for each Aventis share, subject to adjustment
                         in case of any event affecting the share capital or net
                         equity of Aventis (to the extent this adjustment is
                         already provided for in the existing

--------
1  For French option holders, this refers to a waiting period for options
   granted since April 27, 2000 of 2 years following the latest of (i) the
   expiry of the holding period of 4 years following the grant of the options
   and (ii) the exercise date of the option.

                                                                             3/4



                         Aventis/RPR/Hoechst Stock Option plans, it being
                         understood that Sanofi-Synthelabo will consider
                         appropriate adjustments not provided for in the
                         existing Aventis/RPR/Hoechst Stock Option Plans, and
                         that such adjustments will not be less favourable than
                         the adjustments provided for in the Sanofi-Synthelabo
                         Stock Option Plans) or Sanofi-Synthelabo following the
                         close of the Offer such as (but not limited  to) those
                         transactions defined by article L. 225-181 of the
                         French Commercial Code, or a split or a distribution of
                         assets or of an extraordinary dividend to the
                         shareholders of Aventis or Sanofi-Synthelabo, in each
                         case so that the economic balance of the liquidity
                         agreement be maintained for the holders; any difficulty
                         in applying the adjustment will be resolved by an
                         independent expert;

                  (iv)   for the avoidance of doubt, the beneficiaries of the
                         liquidity agreement shall agree not to exercise their
                         stock options during the Restricted Period.

                o Undertaking to pay fractions (rompus) of Option Shares on the
                  same basis;

                o Undertaking to pay the equivalent of the Option Shares in cash
                  as determined in accordance with the above principles (for an
                  amount equal to the market price of the Sanofi-Synthelabo
                  shares that would have been exchanged) on the same basis where
                  the applicable regulations of the residence of the relevant
                  Stock Option holders prohibits the delivery of
                  Sanofi-Synthelabo shares against Aventis shares, except where
                  such payment would be legally prohibited or would create
                  material adverse tax or social charges for companies of the
                  Sanofi-Synthelabo group;

                o In case of a merger of Aventis into Sanofi-Synthelabo or a
                  company of Sanofi-Synthelabo's group, assumption by the
                  absorbing company of Aventis' obligations in relation with the
                  Options (or, as the case may be, amendment of RPR and Hoechst
                  purchase Options plans) in such a way that the options granted
                  by the absorbing company (or, as the case may be, by RPR or
                  Hoechst) allow the Stock Option holders to acquire or
                  subscribe for shares of the latter based on the merger
                  exchange ratio.

               o  In addition, the rights of the holders of Stock Options or
                  Option Shares under the liquidity agreement will be preserved
                  notwithstanding the merger with a company of the
                  Sanofi-Synthelabo group, in such a way that the number of
                  Sanofi-Synthelabo shares they will receive in exchange for
                  their shares in the absorbing company remains equal to the
                  number of Sanofi-Synthelabo shares they would have received if
                  the merger had not taken place.

                  In the particular case of a merger of Aventis into
                  Sanofi-Synthelabo, if the merger exchange ratio is less
                  favorable than the ratio of the subsidiary exchange branch of
                  the Offer, the deficiency will be compensated by an allocation
                  of new stock options or alternatively, if such grant of
                  options would create material adverse legal or tax
                  consequences, Sanofi-Synthelabo shares;

                o The Stock Option holders expressly consent to their Option
                  Shares funded from employee savings plans (PEE) being
                  excluded, subject to the AMF's approval, from the scope of a
                  public buyout offer (OPR) followed by a compulsory squeeze out
                  (RO) on Aventis, for those Option Shares still under the tax
                  and social security holding period applicable to PEE at the
                  time of the OPR-RO if applicable laws or regulations do not
                  permit a tax neutral roll-over under the RO.


                                                                             4/4






                                                               Sanofi-Synthelabo


 Investor Relations



                      SANOFI-SYNTHELABO'S OFFER FOR AVENTIS
                 U.S. OFFER EXTENDED TO WEDNESDAY, JUNE 30, 2004

PARIS, FRANCE-- MAY 26, 2004-- Sanofi-Synthelabo (PARIS:SAN, NYSE:SNY) announces
that pending the decision of the Autorite  des  marches  financiers (AMF) -- the
French stock market regulator -- to set the expiration date of
Sanofi-Synthelabo's revised offer for the ordinary shares of Aventis (PARIS:
AVE, FRANKFURT:AVE.ETR, NYSE:AVE), Sanofi-Synthelabo has extended the U.S. offer
until 5:00 p.m. (Eastern Daylight Time) on Wednesday June 30, 2004,
unless it is extended or withdrawn prior to that time. Holders of Aventis
securities eligible to participate in the U.S. offer may tender, or withdraw
their tendered, Aventis securities at any time until that time.  The U.S. offer
had previously been scheduled to expire at 5:00 p.m. on Friday, May 28, 2004.

As previously disclosed, under applicable French law, the AMF will set the
expiration date of the French offer after it has granted its visa to the
recommendation statement (note d'information en reponse) of Aventis and Aventis
has published that recommendation statement. The AMF has the sole authority to
fix the expiration date of the French offer or to subsequently extend that
expiration date. As soon as the AMF has set the expiration date in the French
offer, Sanofi-Synthelabo will issue a press release announcing that expiration
date. If the AMF sets a later expiration date in the French offer,
Sanofi-Synthelabo will announce that the U.S. offer has been extended until the
same time. Subject to applicable law, Sanofi-Synthelabo reserves the right to
extend the U.S. offer, if the AMF has not set an expiration date for the French
offer by June 30, 2004.

Sanofi-Synthelabo intends that the French offer, the U.S. offer and the German
offer will expire at the same time on the expiration date that will be set by
the AMF.

                                                                             1/2



As of the close of business on May 25, 2004, a total of approximately 900,000
Aventis ADSs had been tendered in and not withdrawn from the U.S. offer. Because
of French centralization procedures, the number of Aventis ordinary shares
tendered in and not withdrawn from the offers cannot be known until after the
expiration of the offers.


In accordance with article 7 of the COB rule no. 2002-04, this press release was
transmitted to the Autorite des marches financiers (AMF) before its publication.

IMPORTANT INFORMATION: In connection with the proposed acquisition of Aventis,
Sanofi-Synthelabo has filed a registration statement on Form F-4 (File no.
333-112314), including a prospectus/offer to exchange, and will file additional
documents with the SEC. INVESTORS ARE URGED TO READ THE REGISTRATION STATEMENT,
INCLUDING THE PROSPECTUS/OFFER TO EXCHANGE, AND ANY OTHER RELEVANT DOCUMENTS
FILED WITH THE SEC, INCLUDING ALL AMENDMENTS AND SUPPLEMENTS (INCLUDING ANY
SUPPLEMENT RELATING TO ITS REVISED OFFERS), BECAUSE THEY CONTAIN IMPORTANT
INFORMATION. Free copies of the registration statement, as well as other
relevant documents filed with the SEC, may be obtained at the SEC's web site at
www.sec.gov. The prospectus/offer to exchange and other transaction-related
documents are being mailed to Aventis securityholders eligible to participate in
the U.S. offer and additional copies may be obtained for free from MacKenzie
Partners, Inc., the information agent for the U.S. offer, at the following
address: 105, Madison Avenue, New York, New York 10016; telephone: 1-(212)
929-5500 (call collect) or 1-(800) 322-2885 (toll-free call); e-mail
proxy@mackenziepartners.com. In connection with its revised offer,
Sanofi-Synthelabo intends to distribute a supplement to the prospectus/offer to
exchange in the coming days.

In France, holders of Aventis securities are requested, with respect to the
offer, to refer to the prospectus supplement (note d'information
complementaire), which has been granted visa number 04-384 by the Autorite des
marches financiers ("AMF") and which is available on the website of the AMF
(www.amf-france.org) and without cost from: BNP Paribas Securities Services,
GIS-Emetteurs, Service Logistique, Les Collines de l'Arche, 75450 Paris Cedex 9
and to the recommendation statement (note d'information en reponse) of Aventis
when it is available.

The public offer to holders of Aventis ordinary shares located in Germany (the
"German Offer") is being made in accordance with applicable German law and
pursuant to an offer document/sales prospectus, which is available free of
charge at BNP Paribas Securities Services, Gruneburgweg 14, D-60322 Frankfurt am
Main (Fax: 069 - 152 05 277) and on the website of the Company
(www.sanofi-synthelabo.com). Any decision to tender Aventis ordinary shares in
exchange for Sanofi-Synthelabo ordinary shares under the German Offer must be
taken exclusively with regard to the terms and conditions of the German Offer,
as well as with regard to the information included in the offer document/sales
prospectus, including any amendments thereto, issued in Germany.

The French Offer, the U.S. Offer and the German Offer are being made on
substantially the same terms and completion of these offers is subject to the
same conditions. It is intended that the three offers will expire at the same
time.

Investors and security holders may obtain a free copy of the Form 20-F filed
with the SEC on April 2, 2004 and any other documents filed by Sanofi-Synthelabo
with the SEC at www.sec.gov as well as of the Reference Document filed with the
AMF on April 2, 2004 (N(degree) 04-0391) at www.amf-france.org or directly from
Sanofi-Synthelabo on our web site at: www.sanofi-synthelabo.com.



INVESTOR RELATIONS DEPARTMENT
Phillipe Goupit         Director of Investor Relations
Arnaud Delepine         Investor Relations Europe
Sanjay Gupta            Investor Relations US
Anne d'Halluin-Sulzer   Investor Relations

CONTACTS:
E-mail: investor-relations@sanofi-synthelabo
Europe                          US
Tel: +33 1 53 77 45 45          Tel.: +1 212 551 42 93
Fax: +33 1 53 77 42 96          Fax:  +1 212 551 49 92