Thirty-six patients with arteritis were treated with Ginkgo biloba extract for sixty-five weeks. For the first six months of the treatment period, these patients participated in a double-blind randomised comparison with 35 well matched patients taking placebo. Subsequently, those patients taking Ginkgo biloba extract were given the option to continue treatment on an open basis with follow-up at regular three-monthly intervals. Ginkgo biloba extract therapy gave significantly greater pain relief and walking tolerance than the placebo after 6 months of treatment, and this improvement continued throughout the whole duration of the study. This symptomatic and measurable improvement was combined with excellent tolerance of the drug.