Incarceration of colonoscope in an inguinal hernia. "Pulley" technique of removal. Because of its relative safety, colonoscopy has become an accepted diagnostic and therapeutic procedure in the evaluation of patients with colorectal disorders. Many unusual complications of colonoscopy have been described, but only anecdotal reports of hernial incarceration have been published. We present a case of a right-sided hernial incarceration of the colonoscope that would not permit reduction of the hernia nor removal of the instrument by conventional means. The mechanism of incarceration, which dictates the size of hernia at risk for incarceration, is explained. The "pulley" technique, which was used to remove the instrument without surgical intervention, is described. 