Constipation is a common disorder and current treatments are unsatisfactory. Biofeedback may help patients with constipation and dyssynergic defecation, but its efficacy is unproven and whether this is due to behavioral modification or excessive attention is unknown. Methods: In a prospective randomized trial, the investigators investigated the efficacy of Biofeedback (manometric- assisted anal relaxation, muscle coordination and simulated defecation training), with either sham feedback therapy (Sham) or standard therapy (diet, exercise, laxatives; Standard) in 77 subjects (69 women) with dyssynergic defecation. Primary outcome measures included presence of dyssynergia, balloon expulsion time, number of complete spontaneous bowel movements (CSBM), and global bowel satisfaction. Data analyzed per protocol.