Daily Q&A: What should I consider before buying dietary supplements?

What should I consider before buying dietary supplements?

Not all dietary supplements on the market — in particular over the Internet — are approved by the U.S. Food and Drug Administration. Consumers should be cautious about picking up just any kind of supplement or medicine.

The FDA recently issued a warning against use of supplements containing silver. In a warning about supplements that contain silver, the FDA said, "risk of permanent skin and mucous membrane discoloration, known as argyria, associated with the use of dietary supplements that contain silver, including colloidal silver."

In another warning, the FDA cautioned against use of some unapproved sexual enhancement dietary supplements, such as "Stiff Nights," that contains an ingredient similar to Viagra. The ingredient in Stiff Nights, sulfoaildenafil, can cause serious injury or death, the FDA said. The active ingredient in Viagra is sildenafil.

For other FDA tips, warnings and alerts, visit: http://www.fda.gov/default.htm.