This study was designed to investigate the effect of topical ketanserin, a selective S2-serotonin antagonist, on wound healing and contraction in surgical wounds allowed to heal by second intention. Thirty-five patients applied placebo or 2% ketanserin gel, double-blind, to head and neck wounds resulting from skin tumour excision, and allowed to heal by second intention. Healing rate was assessed from the change in the square root of wound area, and in 11 patients wound contraction was assessed by the change in the area delineated by wound margin tattoo marks. There were no significant differences in any of the measurements made between the ketanserin- and placebo gel-treated patients. Wound healing was significantly faster in large wounds. Wound contraction was greatest in the early stages of healing, and accounted for 53% of healing. We conclude that, on normally vascularized skin, ketanserin gel has no significant effect on wound healing rate.