Herbs have been in use for centuries to prevent and control disease.  In recent history demand by the public for herbal supplements has created a multimillion-dollar industry.  Herbal extracts are effective because they interact with specific chemical receptors within the body and are in a pharmacodynamic sense, drugs themselves.  A matter for public concern is that herbal supplements are currently independent of regulation by the Federal Drug Administration (FDA).  The FDA considers herbal products to be dietary supplements, not drugs.  The National Toxicology Program has recently started to examine the composition and standardization of commercial preparations to identify potential health hazards from contaminants or product over use.  The widespread use of herbal supplements makes it essential that healthcare providers become informed about this aspect of a patient's personal health practices.