Although gamma-linolenic acid (GLA) has been shown to correct deficiencies in skin lipids associated with reduced delta-6-desaturase activity which should result in improvement of dysregulation of inflammation and immunity in atopic eczema, clinical studies with evening primrose oil containing 10% GLA have yielded contradictory results. We have therefore examined the effect of a higher percentage (at least 23%) GLA-containing borage oil in adults with stable atopic eczema of moderate severity in a double-blind, multicentre study. One hundred and sixty patients were randomized to take daily either 500 mg of borage oil-containing capsules or the bland lipid miglyol as a placebo over a 24-week period. Use of topical diflucortolone-21-valerate cream was allowed as rescue medication, with the amount used until response being defined as primary, and clinical improvement as secondary efficacy criteria. Although several clinical symptoms improved compared with placebo, the overall response to borage oil did not reach statistical significance. Significant differences in favour of borage oil were, however, observed in a subgroup excluding patients who failed to show increased erythrocyte dihomo-gamma-linolenic acid levels and in whom adherence to inclusion criteria and the study protocol were questionable. GLA metabolites increased in borage oil-treated patients only, and serum IgE showed a trend to decrease on overall and subgroup analysis. No substance-related adverse effects were observed. This study shows no overall efficacy of GLA-containing borage oil in atopic eczema, with steroid use being the primary response parameter, although it suggests that a subgroup of patients may benefit from this well-tolerated treatment.