This study will determine whether the herbal product St. John's wort is safe and effective in treating generalized social anxiety disorder (GSAD).

Study hypothesis: Hypericum perforatum (St. John's wort) is more effective in treating GSAD than placebo.

The use of complementary and alternative medicine (CAM) has grown dramatically over the last decade. Botanical treatments originating from plants have become especially popular for treating conditions such as anxiety and depression. Evidence suggests that the botanical St. John's wort has neurochemical activity similar to that of conventional medications. However, research on the safety and effectiveness of St. John's wort is limited. This study will determine the safety and effectiveness of St. John's wort in treating GSAD, a serious condition characterized by intense fear of various social situations that may cause embarrassment.

Participants will be randomly assigned to receive either St. John's wort or placebo daily for 10 weeks. Self-report scales will be used to assess participants' GSAD symptoms at study entry and at study completion. Blood collection will occur at every weekly study visit to determine the levels of St. John's wort in the blood.

Inclusion Criteria:

• Diagnosis of GSAD
• Brief Social Phobia Scale (BSPS) score of 20 or higher

Exclusion Criteria:

• Comorbid anxiety, depressive, or bipolar disorders
• Schizophrenia
• Cognitive impairment
• Substance abuse or dependence within 1 year prior to study entry
• Any unstable medical condition
• Clinically significant laboratory or electrocardiogram (EKG) abnormality
• Currently use psychotropic medications or may need psychotropic medication during the study
• Psychotherapy within 6 weeks prior to study entry
• Failed a previous trial of St. John's wort at doses of 1800 mg/day or greater
• Pregnancy or breastfeeding