Buspirone stimulates central 5-hydroxytryptamine (5HT) receptors and brings about the release of prolactin, and there is evidence to suggest that the extent of prolactin release after a challenge with buspirone is an indicator of the sensitivity of central 5HT receptors. Seventeen patients with a diagnosis of non-ulcer dyspepsia, eight normal healthy volunteers, and six patients with peptic ulcer disease were each given a challenge test of 60 mg buspirone orally, and prolactin release over a 3-h period was monitored. The mean prolactin response was significantly greater in patients with non-ulcer dyspepsia than in healthy controls and peptic ulcer disease patients. The results suggest that central 5HT receptors may be supersensitive in non-ulcer dyspepsia.