Aventis Pasteur Press Release

Lyon, France- Aventis Pasteur has transferred - at no cost - samples of its proprietary cell line from one of its French production sites to the National Institutes of Health (NIH) and Centers for Disease Control and Prevention (CDC) in the United States, for use in isolating and growing the coronavirus, which is suspected of causing Severe Acute Respiratory Syndrome, or SARS.

Aventis Pasteur was contacted by international health authorities in early April, requesting assistance in conducting research for a vaccine to protect against SARS. The samples were shipped in the following days.

“Our goal is to help shorten the timeline for SARS research,” said David J. Williams, chairman, president and CEO of Aventis Pasteur, the vaccines unit of Aventis. “In the battle against infectious diseases, collaborations between government and industry will help leverage vital resources. Aventis Pasteur focuses on infectious diseases, and therefore, is used to moving quickly to protect human life.”

In addition to supporting SARS research, Aventis Pasteur recently entered into an agreement with several WHO reference laboratories (including the CDC, the NIH and the Institute for Biological Standards and Control in the U.K.) to transfer samples of its cell line at no cost for developing a vaccine strain against an avian influenza virus that might help fight a potential influenza pandemic.

About Aventis Pasteur

Aventis Pasteur is the largest company in the world devoted entirely to vaccines. In 2002, Aventis Pasteur produced 1.4 billion doses of vaccine, making it possible to protect 500 million people across the globe, which is about 1.4 million per day. The company offers the broadest range of vaccines, providing protection against 20 bacterial and viral diseases. Based in Lyon, France, Aventis Pasteur is owned by Aventis SA.

Aventis is dedicated to treating and preventing disease by discovering and developing innovative prescription drugs and human vaccines. In 2002, Aventis generated sales of € 17.6 billion, invested € 3.1 billion in research and development and employed approximately 71,000 people in its core business. Aventis corporate headquarters are in Strasbourg, France.

For more information, please visit: www.aventis.com and www.aventispasteur.com

Statements in this news release other than historical information are forward-looking statements subject to risks and uncertainties. Actual results could differ materially depending on factors such as the availability of resources, the timing and effects of regulatory actions, the strength of competition, the outcome of litigation, and the effectiveness of patent protection. Additional information regarding risks and uncertainties is set forth in the current Annual Report on Form 20-F of Aventis on file with the Securities and Exchange Commission.