Spontaneous contractions and those elicited by electrical stimulation were studied in isolated segments of bovine mesenteric lymphatic vessels. The effects of three general anesthetics, pentobarbitone, halothane, and ether, on these spontaneous and evoked contractions were studied. Pentobarbitone and halothane inhibited spontaneous contractions in a dose-dependent fashion. In doses of 10(-4) M or greater both drugs completely abolished spontaneous contractility but when contractions were elicited by electrical stimulation pentobarbitone inhibited them in a dose-dependent manner whereas halothane did not. In contrast to the above results ether in doses as high as 10(-2) M had little effect on lymphatic contractility. It is concluded that, in doses similar to plasma levels found during general anaesthesia, halothane and pentobarbitone significantly depressed lymphatic contractility while ether did not.