WASHINGTON (Reuter) - U.S. health officials warned Wednesday against using diet supplements containing ephedrine sold as alternatives to street drugs such as "Ecstasy'', saying they posed serious health risks. The Food and Drug Administration said the products, often targeted at adolescents and young adults, are marketed under brand names with implications that they produce euphoria, heightened sexual sensation and awareness or increased energy. It said they contain botanical or "natural'' sources of ephedrine, an amphetamine-like stimulant that can have dangerous effects on the nervous system and heart. The FDA said the possible adverse effects ranged from heart attack, stroke, seizures, psychosis and death to less serious ones such as dizziness and irregular heartbeat. It said the risks were serious and it was investigating the production and marketing of ephedrine-containing products sold as alternatives to illegal street drugs. The FDA said that many of the products bear labels implying they can produce a "high'' and it said it considered this type of promotion and these claims to violate the food and drug law, even as amended in 1994. It said it was committed to take any action needed to remove such products from the market. But the agency added that under the amended law it has to act product-by-product to show that something is unsafe rather than be able to require a manufacturer to prove its product is safe before it can be marketed. The agency said that ingredients listed on the panels of the products may include ma huang, Chinese ephedra extract, ephedra herb powder, epitonin or ephedrine, any of which indicate the present of ephedrine. The FDA asked that consumers who have had an adverse reaction after taking a dietary supplement or any product containing an ephedrine alkaloid to call the agency at 1-800-FDA 4010. It said health professionals who have treated patients with adverse side effects should call the FDA's Medwatch hot line at 1-800-FDA-1088.