Although ginseng has been used in traditional medicine over centuries, modern clinical research is inconclusive about its medical effectiveness. There is no substantial evidence that ginseng is effective for treating any medical condition, and its use has not been approved by the US Food and Drug Administration (FDA) as a prescription drug. Although ginseng is commonly sold as a dietary supplement, inconsistent manufacturing practices for supplements have led to analyses showing that ginseng products may be contaminated with toxic metals or unrelated filler compounds, and its excessive use may have adverse effects or untoward interactions with prescription drugs.