The U. S. Food and Drug Administration warned consumers about the safety of more than 25 weight loss products and cautioned them against buying them as they contained undeclared active pharmaceutical ingredients that could pose a serious health risk.

The products can be purchased from some retail stores as well as on the Internet with many of these products claiming to be 'Natural or "with herbal products". An FDA news release said, "These products have not been approved by the FDA, are illegal, and may be potentially harmful to unsuspecting consumers."

The FDA said that the undeclared or ingredients not listed on the label in the products that were tested included sibutramine (a controlled substance), rimonabant (a drug not approved in the U. S), phenytoin (an antiseizure drug), and phenolphthalein (a solution used in chemical experiments and a suspected cancer-causing agent). In some cases, the amount of active pharmaceutical ingredients in the products far exceeded the FDA-recommended levels.

Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research said, "These tainted weight loss products pose a great risk to public health because they contain undeclared ingredients and, in some cases, contain prescription drugs in amounts that greatly exceed their maximum recommended dosages. Consumers have no way of knowing that these products contain powerful drugs that could cause serious health consequences. Therefore, FDA is taking this action to protect the health of the American public."

The unlisted products pose serious health risks with sibutramine, which was found in many of the products, said to cause high blood pressure, seizures, palpitations, heart attack or stroke. The safety of sibutramine also hasn't been determined for women who are pregnant or breast-feeding, or in children younger than 16 years of age, the agency said.

Rimonabant which has been approved in Europe has been associated with increased risk of depression and suicidal thoughts. It has been linked to five deaths and 720 adverse reactions in Europe during the last two years, the agency said.

The FDA has said consumers who are taking any of the products listed by them as unsafe should stop them and consult their health care professional immediately. If anyone is considering using a weight loss product, the FDA says they should seek guidance from a health care professional on the products safety before they purchase it.

Any side effects or quality complaints can be addressed to the FDA's MedWatch Adverse Event Reporting System on the FDA's website.

The FDA said it has inspected a number of companies linked to the sale of these products and has asked for product recalls and may take further enforcement actions against the companies, including issuing warning letters or seeking criminal charges.