Increased use of laxatives and constipation are more common among people with diabetes mellitus than matched nondiabetic people in the same community. The mechanism of constipation in diabetes is unclear. Acute hyperglycemia was previously reported to reduce the gastrocolonic response. Our aim was to determine the effects of acute hyperglycemia on the colon compliance and motor response to feeding and on the sensory function of the colon and rectum in healthy human subjects. Eleven healthy individuals were studied under conditions of hyperglycemia (mean blood glucose 280 ± 13 mg/dl) and euglycemia. We evaluated three parameters: 1) colonic motility and compliance by a multilumen manometry and barostatic balloon assembly in the descending colon (motility was studied during fasting and for 2 h postprandially); 2) perception of isobaric distensions of polyethylene balloons in the rectum and colon; and 3) rectal compliance. Initial tonic response to meal ingestion (0-5 min) was slightly lower during hyperglycemia (P = 0.3). However, colonic tone, motility, compliance, and sensation, as well as rectal compliance and sensation, were not significantly different under the conditions of euglycemia and acute hyperglycemia. In healthy individuals, acute hyperglycemia does not significantly change colonic or rectal motor functions or the perception of mechanosensory stimuli in the colon or rectum compared with euglycemia. These results do not support the hypothesis that hyperglycemia abolishes the colonic response to feeding.