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 14, 2004


         The following advertisements will be published in English at various
times in the Wall Street Journal - Europe and the Financial Times (European
Edition) beginning on June 14, 2004 through June 30, 2004. French and German
language versions of these advertisements will appear in various French and
German publications during the same period.

         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.


                                     * * * *





        [Image of a handwritten reminder note posted on a car dashboard]

              [In handwriting] Tender Aventis shares before June 30

                  It means benefiting from a 31.4% premium (1).
             It also means making it possible for European research
                       to be among the best in the world.

This  project,  based  on  a  growth  strategy,  should  create  value  for  the
shareholders   of  both   groups.   By   tendering   your   Aventis   shares  in
Sanofi-Synthelabo's offer, you will benefit from a premium of 31.4% (1) and will
also  become a  shareholder  of a group  able to  deliver  strong,  lasting  and
profitable growth. With sales of more than 25 billion euros (2), Sanofi-Aventis,
the result of the combination of the two groups, will have a worldwide presence,
particularly  in  the  USA,  while  remaining  strongly  anchored  in  Europe  -
especially  in  France  and  in  Germany.   You  can  become  a   Sanofi-Aventis
shareholder,  thus helping to create the world's  third  largest  pharmaceutical
group, and the no. 1 in Europe.

[Highlighted in a box]

--------------------------------------------------------------------------------
The terms of the offer which has been recommended by the Aventis Management
Board and Supervisory Board are (3):
o Standard entitlement: 5 Sanofi-Synthelabo shares and 115.08 euros in cash for
  6 Aventis shares.
o All-stock election: 1.16 Sanofi-Synthelabo shares for each Aventis share.
o All-cash election: 68.11 euros in cash for each Aventis share.
--------------------------------------------------------------------------------

            Sanofi-Synthelabo's agreed offer to Aventis shareholders
            --------------------------------------------------------
                             BECAUSE HEALTH MATTERS

Free No. 00 800 00 07 58 76                            www.sanofi-synthelabo.com

In accordance with article 7 of the COB rule no. 2002-04, this advertisement 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 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
revised  offer,  to  refer  to the  prospectus  supplement  (note  d'information
complementaire),  which has been granted visa number 04-384 by the 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 thereto, issued in Germany.

This advertisement 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.

(1)  Based on the terms of the offer before adjustment for the payment of the
     Aventis dividend, and on the average closing prices of Sanofi-Synthelabo
     and Aventis shares, weighted by volume, on the First Market of Euronext
     Paris during the one-month period ended January 21, 2004. Based on the
     closing prices of Sanofi-Synthelabo and Aventis shares on the First Market
     of Euronext Paris on June 10, 2004, the premium amounts to 0.10% (based on
     the terms of the offer before adjustment for the payment of the Aventis
     dividend) and 0.10% (after giving effect to the adjustment for the payment
     of the Aventis dividend)
(2)  2003 data.
(3)  The terms of the offer shown reflect the adjustment related to the Aventis
     dividend of (euro)0.82 per share, which has an ex-dividend date before the
     settlement date of the offer.

                                     * * * *




      [Image of a handwritten reminder note posted on a refrigerator door]

              [In handwriting] Tender Aventis shares before June 30

                  It means benefiting from a 31.4% premium (1).
              It also means creating a major group serving health.

You can become a Sanofi-Aventis shareholder, helping to create the world's third
largest  pharmaceutical group, and the no. 1 in Europe. With sales of more
than 25 billion  euros,  4 billion  euros  devoted to research and a substantial
drug portfolio (2),  Sanofi-Aventis will be able to offer an even more effective
response to patients' needs by making new treatments  accessible through a large
worldwide   distribution   network.   By  tendering   your  Aventis   shares  in
Sanofi-Synthelabo's  offer,  you will benefit from a 31.4%  premium (1) and will
take part in a major industrial project: the creation of a group able to deliver
strong, lasting and profitable growth while serving health.

[Highlighted in a box]

--------------------------------------------------------------------------------
The terms of the offer which has been recommended by the Aventis Management
Board and Supervisory Board are (3):
o Standard entitlement: 5 Sanofi-Synthelabo shares and 115.08 euros in cash for
  6 Aventis shares.
o All-stock election: 1.16 Sanofi-Synthelabo shares for each Aventis share.
o All-cash election: 68.11 euros in cash for each Aventis share.
--------------------------------------------------------------------------------

            Sanofi-Synthelabo's agreed offer to Aventis shareholders
            --------------------------------------------------------
                             BECAUSE HEALTH MATTERS

Free No. 00 800 00 07 58 76                            www.sanofi-synthelabo.com

In accordance with article 7 of the COB rule no. 2002-04, this advertisement 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 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
revised  offer,  to  refer  to the  prospectus  supplement  (note  d'information
complementaire),  which has been granted visa number 04-384 by the 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 thereto, issued in Germany.

This  advertisement  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.

(1)  Based on the terms of the offer before adjustment for the payment of the
     Aventis dividend, and on the average closing prices of Sanofi-Synthelabo
     and Aventis shares, weighted by volume, on the First Market of Euronext
     Paris during the one-month period ended January 21, 2004. Based on the
     closing prices of Sanofi-Synthelabo and Aventis shares on the First Market
     of Euronext Paris on June 10, 2004, the premium amounts to 0.10% (based on
     the terms of the offer before adjustment for the payment of the Aventis
     dividend) and 0.10% (after giving effect to the adjustment for the payment
     of the Aventis dividend)
(2)  2003 data.
(3)  The terms of the offer shown reflect the adjustment related to the Aventis
     dividend of (euro)0.82 per share, which has an ex-dividend date before the
     settlement date of the offer.

                                     * * * *




       [Image of a handwritten reminder note posted on a computer monitor]

              [In handwriting] Tender Aventis shares before June 30

                  It means benefiting from a 31.4% premium (1).
                 It also means giving research a new dimension.

You can become a Sanofi-Aventis shareholder, helping to create the world's third
largest pharmaceutical group and the no. 1 in Europe.  Sanofi-Aventis will
have the advantage of a substantial drug portfolio giving it strong positions in
high-growth therapeutic areas:  cardiovascular,  thrombosis,  cancer,  diabetes,
central nervous system,  internal medicine and vaccines.  By combining strengths
and talents, Sanofi-Aventis, with sales of more than 25 billion euros, 4 billion
euros devoted to research and more than 13,000  researchers  (2), should be able
to make progress in health in the service of patients. By tendering your Aventis
shares in  Sanofi-Synthelabo's  offer,  you will take part in a major industrial
project: the creation of a group able to deliver strong,  lasting and profitable
growth while serving health.

[Highlighted in a box]

--------------------------------------------------------------------------------
The terms of the offer which has been recommended by the Aventis Management
Board and Supervisory Board are (3):
o Standard entitlement: 5 Sanofi-Synthelabo shares and 115.08 euros in cash for
  6 Aventis shares.
o All-stock election: 1.16 Sanofi-Synthelabo shares for each Aventis share.
o All-cash election: 68.11 euros in cash for each Aventis share.
--------------------------------------------------------------------------------


            Sanofi-Synthelabo's agreed offer to Aventis shareholders
            --------------------------------------------------------
                             BECAUSE HEALTH MATTERS

Free No. 00 800 00 07 58 76                            www.sanofi-synthelabo.com

In accordance with article 7 of the COB rule no. 2002-04, this advertisement 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 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
revised  offer,  to  refer  to the  prospectus  supplement  (note  d'information
complementaire),  which has been granted visa number 04-384 by the 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 thereto, issued in Germany.

This  advertisement  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.

(1)  Based on the terms of the offer before adjustment for the payment of the
     Aventis dividend, and on the average closing prices of Sanofi-Synthelabo
     and Aventis shares, weighted by volume, on the First Market of Euronext
     Paris during the one-month period ended January 21, 2004. Based on the
     closing prices of Sanofi-Synthelabo and Aventis shares on the First Market
     of Euronext Paris on June 10, 2004, the premium amounts to 0.10% (based on
     the terms of the offer before adjustment for the payment of the Aventis
     dividend) and 0.10% (after giving effect to the adjustment for the payment
     of the Aventis dividend)
(2)  2003 data.
(3)  The terms of the offer shown reflect the adjustment related to the Aventis
     dividend of (euro)0.82 per share, which has an ex-dividend date before the
     settlement date of the offer.