Heartburn, bloating, and abdominal discomfort are common problems in patients with spinal cord injury but, despite its clinical significance, little is known about the gastrointestinal effects of spinal transections. To address the potential gastrointestinal pathophysiology of spinal cord injury, we measured mouth-to-cecum transit time (MCTT) in seven subjects with paraplegia and seven with quadriplegia. Gastric emptying was studied in six subjects with quadriplegia. MCTT was significantly prolonged in patients with quadriplegia, an abnormality corrected by the administration of cisapride. Patients with paraplegia, in contrast to those with quadriplegia, have normal mouth-to-cecum transit time. In addition, patients with quadriplegia had neither a prolonged gastric emptying time nor a change in gastric emptying time, with cisapride. Changes in gastrointestinal transit after spinal cord injury and the improvement of mouth-to-cecum transit time in subjects with quadriplegia, but not in those with paraplegia, may be explained by an imbalance between parasympathetic and sympathetic outflows to the gastrointestinal tract in this group of subjects.