Filed by Sanofi-Synthélabo
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: April 22, 2004

          On April 22, 2004, Sanofi-Synthelabo issued the following press release.

          In connection with the proposed acquisition of Aventis, Sanofi-Synthélabo 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 final prospectus/offer to exchange and related exchange offer materials, to register the Sanofi-Synthélabo ordinary shares (including Sanofi-Synthélabo ordinary shares represented by Sanofi-Synthélabo 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 final 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 to these documents, because they will contain important information. Investors and holders of Aventis securities may obtain free copies of the registration statement, the final 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 final 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.

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Investor Relations		Paris, April 22, 2004

SUSTAINED AND VERY STRONG SALES GROWTH

Excellent first quarter 2004:

2004 forecasts³ clearly confirmed

High quality of the fundamentals:

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Consolidated sales in the first quarter of 2004: up 18.4% on a comparable basis

Sanofi-Synthélabo generated consolidated sales in the first quarter of 2004 of 2,193 million euros, up 18.4% on a comparable basis (11.9% on a reported basis). There was a negative currency effect of 6.4 points, more than two-thirds of which was due to the US dollar.

Consolidated sales in the first quarter of 2004 by geographical region: double-digit growth in all three regions on a comparable basis

Consolidated sales in the first quarter of 2004 by product: 26.5% growth for the top 10 products on a comparable basis

Consolidated sales in the first quarter of 2004 of the Group’s top 10 products were 1,525 million euros, up 26.5% on a comparable basis (18.5% on a reported basis) and represented 69.5% of consolidated sales, compared to 65.1% in the first quarter of 2003 (on a comparable basis).

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In the first quarter of 2004:

Apart from the top 10 drugs, the rest of the portfolio recorded consolidated sales of 668 million euros in the first quarter of 2004, up 3.4% on a comparable basis.

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Developed sales⁵ in the first quarter of 2004: up 27.1% on a comparable basis

In the first quarter of 2004, developed sales, which reflect the worldwide market presence of Sanofi-Synthélabo products in the market, totaled 2,826 million euros, up 27.1% on a comparable basis.

Developed sales of Plavix^®/Iscover^® in the first quarter of 2004: up 63.4% on a comparable basis

Developed sales of Plavix^®/Iscover^® amounted to 884 million euros in the first quarter of 2004 of which 412 million euros were outside the United States (up 38.3% on a comparable basis). In the United States, demand for Plavix^® in the first quarter of 2004 continued to grow at a very fast rate, with an increase in prescriptions of 29.8%⁶ and a favorable price effect. Plavix^® growth corresponds to invoiced sales in line with demand, but benefit from a favorable comparative base. In the first quarter of 2003, sales were affected by the sharp reduction in wholesaler inventories.

Developed sales of Aprovel^®/Avapro^®/Karvea^®: up 20.4% on a comparable basis

Developed sales of Aprovel^®/Avapro^®/Karvea^® in the first quarter of 2004 were 324 million euros. In the United States, demand for Avapro^® in the first quarter of 2004 continued to show strong growth, with prescriptions up 17.5%⁷ and a favorable price effect. Invoiced sales of Avapro^® rose by 13.4% on a comparable basis and were slightly below demand for the quarter.

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Recent events :

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Recent events relating to the bid for Aventis shares:

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First-quarter consolidated sales by geographical region

First-quarter consolidated sales of the top 10 products

Growth in prescriptions of Plavix^®, Avapro^® and Ambien^® in the United States in the first quarter (Prescriptions IMS NPA first quarter 2004 retail + mail order + long term care) (excluding favorable price effect)

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Explanatory notes:

Except as otherwise noted, all figures in this press release are in French GAAP.

In this press release, we refer to our historical sales as “reported” sales.
In addition to reported sales, we also present and discuss two other non-GAAP indicators that we believe are useful measurement tools to explain changes in our reported sales:

Comparable sales: When we refer to the change in our sales on a “comparable” basis, we mean that we exclude the impact of exchange rate fluctuations and changes in Group structure (acquisitions and divestitures of entities and rights to products as well as change in the consolidation percentage for consolidated entities).

For any two periods, we exclude the impact of exchange rates by recalculating sales for the earlier period on the basis of exchange rates used in the later period.

We exclude the impact of acquisitions by including sales for a portion of the prior period equal to the portion of the current period during which we owned the entity or product rights based on sales information we receive from the party from whom we make the acquisition. Similarly, we exclude sales in the relevant portion of the prior period when we have sold an entity or rights to a product.

For a change in the consolidation percentage of a consolidated entity, the prior period is recalculated on the basis of the consolidation method used for the current period.

Reconciliation of Q1 2003 reported-basis sales to Q1 2003 comparable-basis sales

Developed sales: When we refer to “developed sales” of a product, we mean consolidated sales, excluding sales of products to our alliance partners, but including those that are made through our alliances and which are not included in our consolidated sales (with Bristol-Myers Squibb on Plavix ® /Iscover ® (clopidogrel) and Aprovel ®/Avapro ®
/Karvea ® (irbesartan), with Fujisawa on Stilnox ® /Myslee ® (zolpidem). Our alliance partners provide us with information regarding their sales in order to allow us to calculate developed sales.

We believe that developed sales are a useful measurement tool because they demonstrate trends in the overall presence of our products in the market.

Reconciliation of Q1 2004 consolidated sales to Q1 2004 developed sales

The present press release has been sent to the Autorité des Marchés Financiers (French Financial Markets Authority) before publication, pursuant to article 7 of COB Regulation 2002.04.

Important Information

In connection with the proposed acquisition of Aventis, Sanofi-Synthélabo 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 final prospectus/offer to exchange and related exchange offer materials, to register the Sanofi-Synthélabo ordinary shares (including Sanofi-Synthélabo ordinary shares represented by Sanofi-Synthélabo 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 Sanofi-Synthélabo has also filed a Statement on Schedule TO with the SEC. Investors and holders of Aventis securities are strongly advised to read the registration statement and the final 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 to those documents, because they contain important information. Investors and holders of Aventis securities may obtain free copies of the registration statement, the final 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 final 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 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 Autorité des marchés 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.

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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, Grüneburgweg 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-Synthélabo 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.

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-Synthélabo, 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-Synthélabo ordinary shares (including Sanofi-Synthélabo ordinary shares represented by Sanofi-Synthélabo ADSs) in the United States will only be made pursuant to a prospectus and related offer materials that Sanofi-Synthélabo expects to send to holders of Aventis securities. The Sanofi-Synthélabo ordinary shares (including Sanofi-Synthélabo ordinary shares represented by Sanofi-Synthélabo 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-Synthélabo’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-Synthélabo, 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 Autorité des Marchés Financiers on April 2, 2004, could cause actual results to differ materially from those described in the forward-looking statements: the ability of Sanofi-Synthélabo to expand its presence profitably in the United States; the success of Sanofi-Synthélabo’s research and development programs; the ability of Sanofi-Synthélabo 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. Sanofi-Synthélabo 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-Synthélabo with the SEC at www.sec.gov as well as of the Reference Document filed with the AMF on April 2, 2004 N° 04-0391 with the French Autorité des Marchés Financiers at www.amf-france.org or directly from Sanofi-Synthélabo on our web site at: www.sanofi-synthelabo.com.

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REMINDER: A conference call will be organized today at 3:00 p.m. (Paris time). The following numbers are to be dialed 10 minutes before it starts:

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