Sham feeding of glucose solution and saccharin to patients after esophagotomy causes prolonged (3 hours) rise of blood sugar of almost equal degree. Administration of glucose solution through the esophagostomy directly into the stomach causes an increase in blood sugar for 1 1/2 hours with subsequent fall below (by 21.4%) the initial level. Administration of saccharin solution into the stomach and through the esophagostomy causes no rise in blood sugar level whatsoever. The results which were obtained emphasize the significance of the act of eating as the leading link in the control of blood sugar in man. Thus, it was shown that the control of blood sugar is effected in a complex reflex way, including both unconditioned and conditioned natural food reflexes.