This will include taking joint action, when appropriate, such as the issuance of last Thursday's warning letter. Additional legal action could include an injunction or issuance of an administrative order by the FTC or seizure of products, an injunction or criminal prosecution by the FDA.

"The FDA continues to consider the sale and promotion of fraudulent H1N1 influenza products to be a possible threat to the public health and in violation of the Federal Food Drug and Cosmetic Act," said Michael Chappell, acting associate commissioner for regulatory affairs. "The FDA has an aggressive surveillance program to detect fraudulent H1N1-related products and will take prompt action to stop the marketing of fraudulent H1N1 influenza products and will hold those who are responsible for doing so accountable."

There are two antiviral drugs approved by the FDA for treatment and prophylaxis of the 2009 H1N1 influenza virus - Tamiflu (oseltamivir phosphate) and Relenza (zanamivir). Tamiflu and Relenza, in addition to their approved labeling, have been issued Emergency Use Authorizations by the FDA that describe specific authorized uses during this public health emergency.