Summary: Multiple, loose bowel movements that are watery define of diarrhea. In the setting of cancer may not be self-limited and can be dangerous to the patient. Beyond the usual causes, there can be an overgrowth of bacteria or other infectious organisms in the bowel. The cause of diarrhea in the setting of cancer needs to be identified, especially those caused by these unusual infections. Calling the physician should occur if it’s a first episode, if the diarrhea was not expected, if a symptom beyond diarrhea is making you sicker than expected, or if the cancer physician had suggested that if diarrhea occurs then a call is necessary. Fever or weight loss also will often make it necessary to call. Diarrhea can be persistent and be dangerous. Over-the-counter treatments can be used early on but sometimes detailed evaluation and other treatments are needed.
