A 47-year-old woman with a long-standing history of obsessive-compulsive disorder relating to dirt and germs is presented. Her fear of developing bowel cancer led her to manually evacuate faeces from her rectum five times a day and to a resultant rectal prolapse. Treatment involved prolonged graduated exposure to the patient's feared contaminants and ritual avoidance. After 5 months of inpatient therapy, the patient reported a subjective 70% improvement in her symptoms. As her obsessive-compulsive disorder symptoms improved, the patient's rectal prolapse disappeared.