Understanding safety concerns

A product isn't necessarily safe simply because it's natural. Though rare, some dietary supplements have been linked to serious problems, such as liver damage.

Supplements can have strong effects. Ephedra (ma-huang) is an herb once used for weight loss. It's now banned by the FDA because it was associated with adverse effects, such as mood changes, high blood pressure, irregular heart rate, stroke, seizures and heart attacks.

Some weight-loss supplements have been found to contain hidden ingredients, such as prescription drugs, that may be harmful.