The makers of several over-the-counter drugs have been warned by the Food and Drug Administration to stop claiming the pills protect against STDs. FDA said the products - Tetrasil, Genisil, Aviralex, OXi-MED, Imulux, Beta-mannan, Micronutrient, Qina and SlicPlus - purport to prevent numerous STDs, including herpes, chlamydia, human papillomavirus and HIV/AIDS as well as cervical dysplasia. FDA said the drugs are unapproved, and their marketing is a violation of the US Food, Drug and Cosmetic Act. In addition, the agency said the products do not provide proper directions, and some are illegal because their manufacturers' statements about them are false.