All shares of Aventis will begin trading on the Paris and Frankfurt stock exchanges as of December 20, 1999 under the common symbol "AVE'' as well as on the New York Stock Exchange in the form of American Depository Shares (ADS).

The total number of Aventis shares outstanding is 778,006,111 shares.

Aventis is added to the Dow Jones EURO STOXX 50 blue chip index and all relevant large,
broad and sector indexes as of today. The Aventis stock is also included in the following major
international indices: the MSCI Europe, the FT/S&P Europe and the CAC-40.

Information on Aventis share price

The Aventis share is traded on the Paris Stock Exchange under the Sicovam code 13046 and on
the Frankfurt Stock Exchange under the securities identification code 925700.

The Reuters symbol is

• for the ADS in New York: AVE.N
• for the trading in Paris: AVEP.PA
• for the trading in Frankfurt: AVEP.F

The Bloomberg symbol is:

• for the ADS in New York: AVE US
• for the trading in Paris: AVE FP
• for the trading in Frankfurt: AVE GR

Aventis S.A. is a world leader in life sciences. Focused on two core business areas --
pharmaceuticals and agriculture -- Aventis is dedicated to improving life through the discovery and
development of innovative products in the fields of prescription drugs, vaccines, therapeutic
proteins, crop production and protection, animal health and nutrition.

With global corporate headquarters in Strasbourg, France, Aventis employs around 90,000
people in 150 countries and recorded pro forma sales in 1998 of euros 21 billion (US$ 21.3
billion).

Aventis was launched on December 15, 1999 through the merger of Hoechst AG and
Rhone-Poulenc S.A. The 1999 sales of Aventis will be announced in March 2000.

Company news release
N2336