In order to evaluate the contribution of the myenteric plexuses to the control of gastric accommodation to distension and to the rate of gastric emptying of a saline solution in man, we have evaluated these functions in patients with Chagas' disease, which is known to be associated with extensive lesions of the myenteric plexuses. Intragastric pressure was significantly higher (P < 0.05) in Chagas patients (N = 15) than in normal controls (N = 15) for air distension volumes of 100-700 ml. In the range 300-700 ml, the difference between the groups was approximately twofold (P < 0.001). The gastric emptying rate of 500 ml 154 mM NaCl in a second group of Chagas' disease patients (N = 13) was significantly faster than that of the control group (N = 17) at 5 min (P < 0.005) and at 15 min (P < 0.005) after the test meal, but at 25 min the volumes remaining in the stomach were not statistically significant for the two groups (P > 0.10). The impairment of gastric accommodation to distension and consequent rapid gastric emptying demonstrated for chagasic patients emphasizes the role of the myenteric plexuses in gastric reservoir function in man and complements previous evidence obtained in animal studies.