A double-blind placebo-controlled crossover pilot study involving 19 patients was undertaken to evaluate the efficacy of subcutaneous sumatriptan, a selective 5-hydroxytryptamine (5-HT)-like receptor agonist, in the treatment of atypical facial pain (AFP). A reduction in total pain was found 120 min post injection in the sumatriptan group. Most patients, however, described the medication as ineffective overall, despite significant pain score reduction. The temporary improvement of pain scores with the active drug was thought to be too small to be of any clinical benefit, but suggests that vascular or neurogenic mechanisms may be involved in the aetiology of AFP. Sumatriptan is not an appropriate therapeutic option for patients with AFP, but could prove a valuable drug in experimental clinical pharmacology.