Previous animal and human data have shown that ketanserin, the first specific serotonin2 antagonist, may have beneficial effects on peripheral vascular diseases and on the healing of ulcers. In this double-blind study a 2% ketanserin ointment in a polyethylene glycol base was used to treat 23 patients with venous ulcers (13 ketanserin, 10 placebo). Classical wound care measures were maintained in both groups; therefore, conventional ulcer therapy (with placebo in a polyethylene glycol base) was in reality compared with conventional ulcer treatment plus ketanserin. The most important parameter for evaluation in this study was the development of granulation tissue (first sign of successful wound healing). The evolution of granulation was significantly better with ketanserin than with placebo (p less than 0.05, Mann-Whitney U test). According to the investigator's evaluation, ketanserin showed a response in 10 out of 11 patients as opposed to 5 out of 10 placebo patients at the end of the study. This first double-blind placebo-controlled study suggests that topically applied ketanserin promotes the healing of venous ulcers.