Obstinate constipation is a frequent but elusive gastrointestinal symptom. Increased understanding of defecation physiology and recent availability of simple, ready-to-use tools have increased specificity of both diagnosis and treatment. This patient series includes over 700 severely constipated patients with over 70 percent overall therapeutic success. Cinedefecography, pelvic floor electromyography, and determination of rectoanal inhibitory reflex were performed with simple and readily available equipment to document outlet anatomy and dynamics. Colonic transit time was examined in patients whose defecography and electromyography results were nondiagnostic and/or whose response to medical management was suboptimal, using a commercially available marker capsule, followed by abdominal x-rays. Retention of markers throughout the colon suggested colonic hypomotility or "inertia"; rectosigmoid retention confirmed functional outlet obstruction. With careful history, physical examination, and exclusion of organic causes, orderly application of readily available techniques can afford rapid, objective, and anatomically specific evidence upon which treatment of disordered defecation may be based. © 1990 American Society of Colon and Rectal Surgeons.