Bowel dysfunction (e.g., fecal incontinence, infrequent or difficult defecation) are both frequent and severely troubling problems for patients with spinal cord injury, multiple sclerosis and Parkinson's disease. The etiology of these symptoms is complex; there may be autonomic and pelvic nerve dysfunction (with attenuation of voluntary motor function and impaired anorectal sensation and anorectal reflexes), or generalized systemic factors (e.g., altered diet and behavior, impaired mobility, psychological disturbances or drug adverse effects). The mainstay of current treatment is adapting a conservative approach towards reversing the systemic effects and optimizing the mechanics of defecation through the use of laxatives and irrigation approaches. When successful, this approach improves both evacuation and incontinence symptoms, with associated improvements in quality of life and independence. Future therapies may be directed at modulating pelvic innervation through electrical stimulation. Stoma formation remains an option for patients refractory to other approaches.