This article reviews all available studies on the use of selective serotonin reuptake inhibitors (SSRIs) for the pharmacotherapy of social anxiety disorder. Using the search methods laid out by the Cochrane Collaboration, 25 published reports of SSRI effectiveness for social anxiety disorder were identified, of which eight were randomized, double-blind, placebo-controlled trials (RCTs). The odds ratios of responder status ('much improved' or 'very much improved' on the Clinical Global Impression Scale) for SSRI versus placebo varied between 2.1 and 26.2. In no RCT was the lower confidence limit less than 1. The number needed to treat varied from 1.6 to 4.2. The number of patients who responded to drug was approximately twice the number who responded to placebo. Comparing the change in mean Liebowitz Social Anxiety Scale score in patients treated with drug versus those treated with placebo, the effect sizes of the RCTs varied from 0.3 to 2.2. In four RCTs the effect size was 'large', in one 'moderate' and in two 'small'. Furthermore, response rates and effect sizes for SSRIs were larger than those seen in trials of the reversible monoamine oxidase inhibitors (RIMAs). It may be concluded with a high degree of confidence that SSRI treatment for social anxiety disorder is effective, both in reducing total levels of social anxiety and in improving patients' overall clinical condition. (C) 2000 Lippincott Williams and Wilkins.