ABSTRACT
<b>Objective</b>: We experienced a case with recurring constipation and diarrhea caused by morphine for relieving cancer pain, who were well managed with oral administration of misoprostol. <b>Subject</b>: The patient was a male in his 70s with recurrent bladder cancer following primary surgery, developed bone metastasis to right side pelvis and exhibited cancer-related pain. To alleviate the resting pain, he underwent radiotherapy and received a sustained preparation of morphine sulfate, that lead to difficulty in bowel movements (repeated constipation and diarrhea) and abdominal distension which was intractable with routine administration of laxatives. Misoprostol, a prostaglandin E1 derivatives, which was reported to have an ability to control the bowel movement was administered at a dose of 800μg/day, and the patient subsequently achieved the improvement of bowel dysfunction and resumed regular self-defecation. <b>Discussion</b>: Misoprostol do not only accelerate small intestine movement but also inhibits water and sodium absorption. In this case, it is suggested that the pharmacological properties of misoprostol enabled to improve bowel movement. We consider that misoprostol is useful as one of the medications for refractory constipation caused by opioid administration. Palliat Care Res 2008:3(1);301-304