Sigmoid activity was studied in 26 patients with complete lesions at various levels of the spinal cord. The resting unstimulated motility of the pelvic colon was found to differ in patients with high cord lesions both from that of normal subjects and patients with low thoraco-lumbar lesions. In high cord transection with intact isolated cord below the lesion, resting colonic activity was reduced compared with normal subjects, while patients with low cord lesions showed a significantly increased colonic motility. The mechanism underlying the changes of resting colonic motility is discussed. Factors influencing colonic motility were also studied and the effects of intake of food, the psycho-visceral reflex, rectal distension, sigmoidoscopy, and intrathecal alcohol injection are described.