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 5, 2004


         On May 5, 2004, Sanofi-Synthelabo issued the following press release.

          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 LOGO]


[GRAPHIC] INVESTOR RELATIONS                                Paris, May 5th, 2004





                      SANOFI-SYNTHELABO'S OFFER FOR AVENTIS

      REQUEST FOR ADDITIONAL INFORMATION FROM THE FEDERAL TRADE COMMISSION


As previously  disclosed,  Sanofi-Synthelabo  has engaged in a dialogue with the
FTC on its offer for Aventis since  December 2003.  Sanofi-Synthelabo  has fully
cooperated  with  the  FTC's  investigation.  As has been  previously  reported,
Sanofi-Synthelabo   has   agreed   to  divest   Arixtra   and   Fraxiparine   to
GlaxoSmithKline with the condition of the success of the offer to resolve an FTC
concern.

On April 26, 2004,  Sanofi-Synthelabo  announced an increased  offer,  which has
been  recommended by Aventis  Supervisory  Board.  This  increased  offer is not
subject to the  condition  precedent of the  expiration  or  termination  of the
applicable waiting period under the US Hart-Scott-Rodino  Antitrust Improvements
Act.

Sanofi-Synthelabo's  Hart-Scott-Rodino  notification form was filed with the FTC
on April 5, 2004 and the  initial  30-day HSR waiting  period  expires on May 5,
2004. As is standard practice when investigating a friendly  transaction of this
significance,  the FTC has today issued a "second  request" for  information  to
enable it to complete its ongoing investigation of Sanofi-Synthelabo's offer.

Sanofi-Synthelabo  and Aventis will fully cooperate with the FTC's investigation
to resolve all remaining issues as promptly as possible.

Sanofi-Synthelabo does not expect that resolution of the issues being discussed
with the FTC will have any material impact on the business of the future group.

Sanofi-Synthelabo  does not expect the FTC's  issuance of the second  request to
delay or otherwise  affect the  completion  of its  exchange  offer for Aventis,
which is expected to occur on or before the end of the second quarter of 2004.


In  accordance  with article 7 of the COB rule no.  2002-04,  this  document 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 United  States  Securities  and  Exchange  Commission  (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 as soon as practicable.

In France,  holders of Aventis  securities  are  requested,  with respect to the
offer, to refer to the prospectus (note  d'information),  which has been granted
visa number  04-0090 by the AMFand  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 all other appropriate  documents  relating to the French offer filed with
the AMF.

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 (No. 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