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: August 12, 2004


     On August 12, 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  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.


                                     * * * *




                                                        [SANOFI-SYNTHELABO LOGO]

[GRAPHIC] Investor Relations


             BROAD SUCCESS OF SANOFI-SYNTHELABO'S OFFER FOR AVENTIS

            BEFORE ANY SUBSEQUENT OFFERING PERIOD, SANOFI-SYNTHELABO
                      HOLDS 95.47% OF AVENTIS SHARE CAPITAL


PARIS,  FRANCE -- AUGUST 12, 2004 --  Sanofi-Synthelabo  (PARIS: SAN, NYSE: SNY)
announces that the French Autorite des marches  financiers (AMF) today published
the definitive results of Sanofi-Synthelabo's  offers for Aventis. These results
confirm that, as previously announced on August 9, 2004, as of the expiration of
the offers on July 30, 2004, in aggregate  769,920,773  Aventis  ordinary shares
had been tendered into the French,  German and U.S. offers (including 24,137,576
Aventis  ordinary  shares  underlying  the Aventis ADSs  tendered  into the U.S.
offer).  In  addition,  92,692  warrants  issued by Aventis in 2002 and  164,556
warrants issued by Aventis in 2003 were tendered into the French offer.

These results indicate that 769,920,773  Aventis shares  representing  95.47% of
the share capital and 95.52% of the voting  rights of Aventis,  on an issued and
outstanding basis as of July 31, 2004, have been tendered into the offers. After
giving effect to the offers, on a fully-diluted  basis,  Sanofi-Synthelabo  will
hold 89.84% of the share capital and 89.88% of the voting rights of Aventis. The
AMF has therefore determined that the minimum tender condition to the offers has
been  satisfied  and  that  the  offers  have  been   successful.   Accordingly,
Sanofi-Synthelabo  will  accept all the  Aventis  ordinary  shares and  warrants
tendered in the offers and  expects  that the  settlement  of the offers and the
delivery of the offer  consideration  in accordance with the terms of the offers
will occur in respect of tendered Aventis ordinary shares on Friday,  August 20,
2004 and in respect of Aventis  ADSs  tendered  in the U.S.  offer no later than
Thursday, August 26, 2004 (to allow for necessary foreign exchange conversions).
Euronext Paris will publish the timetable for the settlement and delivery.

EFFECT OF PRORATION AND ALLOCATION.

According to the AMF's announcement,  in aggregate  157,233,058 Aventis ordinary
shares were tendered for the standard  entitlement,  75,690,733 Aventis ordinary
shares were tendered  pursuant to an all stock election and 536,996,982  Aventis
ordinary  shares were  tendered  pursuant to an all cash  election.  Because the
aggregate  number of Aventis  ordinary shares tendered  pursuant to an all stock
election was less than 2.5512 times the




aggregate  number of Aventis  ordinary shares  tendered  pursuant to an all cash
election, the all cash election was oversubscribed. After applying the proration
and allocation  procedures in the manner  described in the offer  documentation,
507,328,303  of the  Aventis  ordinary  shares  tendered  pursuant  to all  cash
elections were deemed to have been tendered for the standard  entitlement,  with
the result that  Sanofi-Synthelabo  is  acquiring  the Aventis  ordinary  shares
tendered in the offers according to the following distribution:

        o  664,561,361 for the standard entitlement;

        o  75,690,733 pursuant to the all stock election; and

        o  29,668,679 pursuant to the all cash election.

As a result of this  allocation  and  proration,  holders that tendered  Aventis
ordinary  shares (or Aventis ADSs) pursuant to an all cash election will receive
approximately  (euro)21.89  in cash and 0.7872 of a  Sanofi-Synthelabo  share in
exchange for each  Aventis  ordinary  share that they  tendered (or an amount in
U.S. dollars equal to (euro)21.89 in cash and 1.5744  Sanofi-Synthelabo  ADSs in
exchange for each Aventis ADS they tendered).  However,  it is important to note
that these per share  figures do not take into account the effect of  fractional
shares and may reflect the effect of rounding.  The  consideration  that holders
will receive in exchange for Aventis ordinary shares (or Aventis ADSs) that they
tendered for the standard  entitlement or pursuant to an all stock election will
not be subject to any  adjustment  and will be paid in the amounts  described in
the offer documentation.

SUBSEQUENT OFFERING PERIOD FROM AUGUST 13, 2004 TO SEPTEMBER 6, 2004

Having  obtained  greater than  two-thirds of the total share capital and voting
rights of Aventis,  Sanofi-Synthelabo  today  announces  that it will  provide a
subsequent  offering period in each of the French,  German and U.S. offers of 17
French trading days. The terms and amount of the consideration  offered in these
subsequent  offering  periods are identical to those offered  during the initial
offering  periods.  The subsequent  offering periods will commence on August 13,
2004 and expire on September 6, 2004, at 23:00 hr (Central European Summer Time)
for the French  and  German  offers  and  simultaneously  at 5:00 p.m.  (Eastern
Daylight Time) for the U.S. offer.

Sanofi-Synthelabo currently expects that the AMF will publish the results of the
subsequent  offering  periods on or about September 16, 2004.  Sanofi-Synthelabo
currently  expects that the settlement date of the subsequent  offering  periods
will occur on or about September 24, 2004.

The proration and allocation  adjustments  described in the offer  documentation
will continue to apply to elections made with respect to Aventis ordinary shares
tendered in the




subsequent offering period.  However,  as disclosed in the offer  documentation,
the results of the application of these proration and allocation  adjustments to
tenders in the subsequent  offering  period may differ from the results of their
application to tenders in the initial  offering  period ended July 30, 2004 that
are described in this press release.

MINORITY BUY-OUT OFFER AND COMPULSORY ACQUISITION; MERGER

At this time,  no decision  has been taken with  respect to a possible  minority
buy-out offer followed by a compulsory acquisition or with respect to a possible
merger of Aventis and Sanofi-Synthelabo.

DIVIDEND PAYMENT DATE

Under the terms of the offers, each  Sanofi-Synthelabo  ordinary share issued to
tendering  holders of Aventis ordinary shares will entitle the holders (provided
they continue to hold the Sanofi-Synthelabo  ordinary shares through payment) to
receive the dividend of (euro)1.02 that the  shareholders  of  Sanofi-Synthelabo
approved for distribution in respect of  Sanofi-Synthelabo's  2003 results. This
dividend will be paid on or about  September 30, 2004, to the holders of the new
Sanofi-Synthelabo  ordinary shares to be issued in exchange for Aventis ordinary
shares in the offers and,  assuming it is paid on September  30,  2004,  will be
paid to whoever holds those Sanofi-Synthelabo ordinary shares as of the close of
business on September 29, 2004. An interim  dividend of (euro)0.97 per share has
already been distributed on the existing  Sanofi-Synthelabo ordinary shares. The
balance of (euro)0.05  remaining on the 2003 dividend will also be paid on these
existing  Sanofi-Synthelabo  ordinary  shares on September  30, 2004, to whoever
holds  those  existing  Sanofi-Synthelabo  ordinary  shares  as of the  close of
business on September 29, 2004.

COMPANY RENAMED SANOFI-AVENTIS

On August 20, 2004, on settlement of the offers and  acquisition  of the Aventis
ordinary  shares  by   Sanofi-Synthelabo,   Aventis  will  become  a  controlled
subsidiary  of  Sanofi-Synthelabo.   At  that  time,  as  previously  disclosed,
Sanofi-Synthelabo will officially change its name to "Sanofi-Aventis".

DIRECTORS OF SANOFI-AVENTIS PROPOSED BY AVENTIS TO TAKE UP OFFICE

Also on  settlement  of the  offers on August  20,  2004,  the  following  eight
directors of Sanofi-Aventis  will take office:  Jean-Marc Bruel, Jurgen Dormann,
Jean-Rene  Fourtou,  Serge Kampf,  Igor Landau,  Hubert  Markl,  Klaus Pohle and
Hermann Scholl. As previously disclosed,  each of these individuals was proposed
as a candidate by the Supervisory  Board of Aventis and subsequently  elected by
the shareholders of Sanofi-Synthelabo at their




annual general meeting on June 23, 2004, subject to the condition precedent that
the offers were settled.

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 and a prospectus  supplement  relating to the revised offer, and will
file  additional  documents  with  the  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 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) which has been granted visa number 04-510.

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. The three offers expired at the same time.

This press  release does not  constitute an offer to purchase or exchange or the
solicitation  of an offer to sell or exchange  any  securities  of Aventis or an
offer to sell or exchange or the solicitation of an offer to buy or exchange any
securities  of  Sanofi-Synthelabo,  nor shall  there be any sale or  exchange of
securities in any jurisdiction  (including the United States, Germany, 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.
The distribution of this communication may, in some countries,  be restricted by
law or  regulation.  Accordingly,  persons  who  come  into  possession  of this
document  should  inform  themselves  of and  observe  these  restrictions.  The
solicitation  of  offers to buy  Sanofi-Synthelabo  ordinary  shares  (including
Sanofi-Synthelabo  ordinary shares represented by Sanofi-Synthelabo ADSs) in the
United  States will only be made  pursuant  to a  prospectus  and related  offer
materials  that  Sanofi-Synthelabo   expects  to  send  to  holders  of  Aventis
securities. The Sanofi-Synthelabo  ordinary shares (including  Sanofi-Synthelabo
ordinary shares represented by Sanofi-Synthelabo  ADSs) may not be sold, nor may
offers  to  buy be  accepted,  in the  United  States  prior  to  the  time  the
registration  statement  becomes  effective.  No offering of securities shall be
made  in  the  United  States  except  by  means  of a  prospectus  meeting  the
requirements  of Section  10 of the United  States  Securities  Act of 1933,  as
amended.

FORWARD-LOOKING STATEMENTS
--------------------------

This  press  release   contains   statements  that  constitute   forward-looking
statements within the meaning of the U.S. Private  Securities  Litigation Reform
Act of 1995.  Forward-Looking  statements are statements that are not historical
facts.  These statements  include financial  projections and estimates and their
underlying assumptions,  statements regarding plans, objectives and expectations
with  respect  to future  operations,  products  and  services,  and  statements
regarding   future   performance.   Forward-looking   statements  are  generally
identified  by  the  words  "expect,"   "anticipates,"   "believes,"  "intends,"
"estimates" and similar  expressions.  Although  Sanofi-Synthelabo's  management
believes that the expectations reflected in such forward-looking  statements are
reasonable,   investors  are  cautioned  that  forward-looking  information  and
statements  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.  The following factors, among other risks and uncertainties that are
described  in our Form  20-F as filed  with the SEC on April 2,  2004 and in the
Reference  Document  filed with the French  Autorite des Marches  Financiers  on
April 2,  2004,  could  cause  actual  results to differ  materially  from those
described in the forward-looking statements: the ability of Sanofi-Synthelabo to
expand  its  presence   profitably  in  the  United   States;   the  success  of
Sanofi-Synthelabo's   research  and   development   programs;   the  ability  of
Sanofi-Synthelabo  to protect its intellectual  property  rights;  and the risks
associated  with  reimbursement  of  health  care  costs  and  pricing  reforms,
particularly




in the United  States and  Europe.  Other than as required  by  applicable  law,
Sanofi-Synthelabo  does not  undertake any  obligation to provide  updates or to
revise any forward-looking statements.

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 and may obtain the Reference Document filed with the
AMF on April 2, 2004 (No.  04-0391)  and other  documents  filed with the AMF at
www.amf-france.org.   Free   copies   may  also  be   obtained   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
Loic Gonnet             Investor Relations

CONTACTS:
E-mail: investor-relations@sanofi-synthelabo.com
Europe                       US
Tel: + 33 1 53 77 45 45      Tel.:  + 1 212 551 40 18
Fax: + 33 1 53 77 42 96      Fax :  + 1 646 487 40 18