An increasing number of people in the United States are using herbs for health promotion and specific symptom management. Herbs are used to initiate healing through synergistic responses unlike the specific properties of pharmaceuticals. Anecdotal data comprise much of the popular information available about herbs. Scientific studies of the efficacy and safety of herbs, although on the rise, are less available than other drug trials. Clinicians need an appropriate knowledge base for dealing with patients who take herbal preparations as well as the ability to confidently include herbal preparations in their formulary. In this article, five common herbs are reviewed. The effects, clinical studies, side effects, and dosing regimens for aloe vera, arnica, black cohosh, evening primrose oil, and saw palmetto are described.