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: June 7, 2004

     On June 7, 2004,  Sanofi-Synthelabo  first  disseminated the following
communication materials to its employees.

     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  and a  prospectus  supplement  relating  to the revised  offer,  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 AND PROSPECTUS SUPPLEMENT RELATING TO
THE  REVISED  OFFER,  THE  STATEMENT  ON  SCHEDULE  TO,  AND ANY OTHER  RELEVANT
DOCUMENTS FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS AND SUPPLEMENTS  BECAUSE
THEY CONTAIN IMPORTANT INFORMATION.  Investors and holders of Aventis securities
may obtain  free  copies of the  registration  statement,  the  prospectus,  the
prospectus  supplement  relating to the revised offer 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,  the
prospectus    supplement    relating   to   the   revised    offer   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.

                                     * * * *


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Number 2                                                          June 7, 2004
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                             LA LETTRE BLEUE No. 2
                             ---------------------


        [GRAPHIC OF WOMAN                              FURTHER
           WITH CHILD]                                 DETAILS...



WHAT ARE THE AMF, THE SEC AND THE FTC?
> The Autorite des marches  financiers (AMF) is a public  authority  responsible
for overseeing the protection of savings,  the information provided to investors
and the proper  functioning  of stock markets in France.  This mandate  includes
supervision  and the  quality  of  information,  compliance  with  stock  market
regulations,  and compliance with the professional code of conduct applicable to
stockbrokers.  The AMF resulted from the merger last year of the  Commission des
operations de bourse (COB) and the Conseil des marches financiers (CMF).

> The Securities  and Exchange  Commission  (SEC) is, in the United States,  the
administrative authority equivalent to the AMF in France, with generally similar
responsibilities.

> The United States Federal Trade Commission (FTC) is an  administrative  agency
of the United States federal  government.  In general,  it is one of the federal
agencies  responsible for enforcing the U.S. antitrust laws. In particular,  the
FTC has jurisdiction to review  Sanofi-Synthelabo's  proposed acquisition of the
shares of Aventis pursuant to the offer and to ensure that it complies with U.S.
antitrust laws. In Europe, it is the European Commission that is responsible for
ensuring that Sanofi-Synthelabo's  acquisition of Aventis complies with European
Union competition laws.

WHAT HAPPENS TO THE OFFER AFTER THE AGREEMENT SIGNED WITH AVENTIS?
> The new offer, on improved  financial  terms,  was filed with the AMF on April
26, 2004  (revised  offer).  The AMF approved the terms of this revised offer on
May 4, 2004 and gave its visa to the new offer  prospectus  on May 7, 2004.  The
revised  offer  began in France  on May 12,  2004.  Sanofi-Synthelabo's  ongoing
offers in the United  States and in Germany have also been revised and are being
made on substantially similar terms to the revised French offer.

WHEN WILL THE CLOSING DATE FOR TENDERS IN THE OFFER OCCUR?
> The AMF has set June 30, 2004 as the expiration date.

IS THE REVISED OFFER SUBJECT TO REVIEW BY THE U.S. FEDERAL TRADE COMMISSION
(FTC)?
> The closing of Sanofi-Synthelabo's revised offer is no longer subject to the
condition that we have received the approval of the FTC.

Nevertheless,  the acquisition of Aventis must be reviewed by the FTC and, under
applicable  United  States law, we may not complete the revised offer before the
termination or expiration of a waiting period during which the FTC conducts that
review.

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

WHAT IS THE LEGAL  NATURE OF THE PUBLIC  TENDER OFFER  SANOFI-SYNTHELABO  HAS
MADE FOR AVENTIS?
>  Sanofi-Synthelabo's  offer for Aventis is a public  tender  offer  which,  if
successful,  will result in Sanofi-Synthelabo  taking control of Aventis through
the acquisition of a majority of the share capital and voting rights of Aventis.
Immediately after the completion of the offer, Aventis will continue to exist as
a separate  company,  which will be a subsidiary of  Sanofi-Synthelabo;  on this
basis, the integration of the two businesses will be able to start.



HOW CAN YOU TENDER AVENTIS SHARES TO THE SANOFI-SYNTHELABO OFFER?
> If you hold  Aventis  shares,  your bank is going to contact you to ask if you
wish to tender  them to the offer;  if you do, you should  return the reply form
which is attached to the letter from your bank within the specified time period.

If you  hold  Aventis  shares  through  a  mutual  fund,  you do not  need to do
anything;  the fund  manager  will decide  whether to tender the fund's  Aventis
shares in Sanofi-Synthelabo's offer.

IS IT TRUE TO SAY THAT THE DIVESTMENT OF ARIXTRA(R) AND FRAXIPARINE(R) TO GSK
IS SUBJECT TO THE SUCCESSFUL COMPLETION OF THE OFFER FOR AVENTIS?
> Yes,  that is the  case,  the  divestment  of  these  products,  their  active
ingredients  and their related  assets  (including  the Notre Dame de Bondeville
facility) will only take place if and when the offer for Aventis is successfully
completed.

WHERE WILL THE HEADQUARTERS OF THE NEW GROUP BE LOCATED?
> The headquarters of the new Group will be located in Paris.

PLEASE EMAIL US YOUR
QUESTIONS

If you have a question,
please send a message
(preferably in French,
English or Spanish) to:
lalettrebleue@sanofi-synthelabo.com.
We will do our best to reply.

In accordance with article 7 of COB Regulation no. 2002-04, the present
document has been submitted to the Autorite des marches financiers ("AMF").

This communication contains forward-looking information and statements which are
not historical  facts and which are subject to various risks and  uncertainties,
many of which are  difficult  to predict  and  generally  beyond the  control of
Sanofi-Synthelabo,  that could cause actual results and  developments  to differ
materially   from  those   expressed   in,  or  implied  or  projected  by,  the
forward-looking  information  and  statements.  These  risks  and  uncertainties
include  those  discussed or  identified  in the public  filings with the United
States  Securities  Exchange  Commission  ("SEC")  and the  AMF.  Other  than as
required by applicable law,  Sanofi-Synthelabo does not undertake any obligation
to update any forward-looking information or statements.

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 and a prospectus  supplement  relating to the revised offer, and will
file additional  documents with the Securities and Exchange  Commission ("SEC").
INVESTORS ARE URGED TO READ THE REGISTRATION STATEMENT, INCLUDING THE PROSPECTUS
AND THE  PROSPECTUS  SUPPLEMENT  RELATING  TO THE REVISED  OFFER,  AND ANY OTHER
RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING ALL AMENDMENTS AND SUPPLEMENTS,
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 and the prospectus
supplement relating to the revised offer and other transaction-related documents
are being mailed to Aventis security holders 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 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
which has been granted visa number 04-510 by 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 and supplements 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 with the French Autorite des Marches Financiers
at  www.amf-france.org  or directly from  Sanofi-Synthelabo  on our web site at:
www.sanofi-synthelabo.com.

This  communication  does not constitute an offer to purchase or exchange or the
solicitation  of an offer to sell or exchange any  securities nor shall there be
any sale or exchange of  securities  in any  jurisdiction  (including  Italy and
Japan) in which such offer,  solicitation  or sale or exchange would be unlawful
prior to the registration or qualification under the laws of such jurisdiction.





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