Administration of a beta-blocker, pindolol, was utilized in the premedication of patients selected for tonsillectomies (dissection), to study anxiolytic effects. A curious result observed was that bleeding during and after operation in patients on pindolol was remarkably reduced compared to those not on beta-blocker treatment. This effect was further explored in a small controlled study. Nineteen patients were given pindolol, 5 mg the evening before and on the morning, an hour prior to surgery. Seventeen controls were on placebos. The amount of bleeding was measured in both groups. Patients on pindolol show significantly reduced bleeding when compared to controls (1.77 +/- 1.15 ml versus 7.30 +/- 6.05 ml; p less than 0.005). Coagulation and fibrinolytic profiles were studied in a number of patients in both groups attempting to clarify the cause of the reduced bleeding. The results will be reported. This preliminary study shows that pindolol is a useful drug for controlling bleeding in tonsillectomies. To our knowledge the haemostatic properties of pindolol have been reported before.