Because of evidence suggesting that volatile anesthetics interfere with platelet aggregation in vitro, platelet function was investigated in patients exposed to combinations of nitrous oxide, halothane, and enflurane during brief surgical procedures. In 12 patients undergoing elective operations, blood was sampled before anesthesia, after induction but prior to surgery, during surgery, and postoperatively. Platelet aggregation by ADP, epinephrine, and collagen was similar during each sampling period in all but two subjects in whom only minor changes were noted. During brief exposure to these general anesthetics, there appears to be no clinically important inhibition of platelet function.