One hundred children were allocated randomly to receive either ethamsylate (Dicynene) or a placebo before undergoing adenotonsillectomy. Blood loss at operation was estimated from the haemoglobin content of swabs and aspirated fluid. Mean blood loss in the ethamsylate-treated group was not significantly less than in the controls. The frequency of secondary haemorrhage was significantly less in children treated with ethamsylate (P less than 0.01). No side-effects were reported in either group.