Forty-five patients with soiling but without faecal incontinence were evaluated by means of anorectal function investigations (anal manometry, rectal capacity and saline infusion test). The causes of soiling and the effect of treatment on both soiling and anorectal function were studied. The results were compared with a control group of 161 patients without soiling or incontinence. The diagnoses were haemorrhoids (10), mucosal prolapse (7), rectal prolapse (6), fistulae (5), proctitis (3), faecal impaction (2), rectocele with intussusception (2), scars after fistulectomy (2) and others (8). Simple inspection and proctoscopy were generally sufficient to establish a diagnosis. For two patients the diagnosis rectocele was made after defaecography. Anorectal test results did not differ between the soiling and control group, did not contribute to establish a diagnosis and did not change after treatment. Only patients with a rectal prolapse had abnormal results in anorectal function tests: a low basal sphincter pressure and a limited continence reserve. Appropriate therapy resulted in complete recovery (44%) or improvement of symptoms (29%).