Diarrhea, ASCO's curriculum

This section has been reviewed and approved by the PLWC Editorial Board, 05/05

Diarrhea is frequent, loose, or watery bowel movements. It may be caused by chemotherapy, radiation therapy to the pelvis, or by the cancer itself. Diarrhea may also be caused by graft-versus-host-disease (GVHD) in people who have received a bone marrow transplantation. Diarrhea may be described according to the following stages established by the National Cancer Institute:

  • Stage 0 is increased stool frequency, but no diarrhea.
  • Stage 1 is an increase of less than four stools a day.
  • Stage 2 is an increase of four to six stools a day or nocturnal (nighttime) stools.
  • Stage 3 is an increase of more than seven stools a day, or incontinence, or a need for intravenous (IV) fluids to treat dehydration.
  • Stage 4 is a severe condition that requires intensive care.


Preventing diarrhea or treating it early can help a person avoid becoming dehydrated or developing other problems. The following suggestions can help manage mild (stage 1 or 2) diarrhea:

  • Avoid caffeine, alcohol, dairy, fat, fiber, orange juice, prune juice, and spicy foods.
  • Avoid laxatives, metoclopramide (Reglan, used to prevent vomiting and constipation), and stool softeners.
  • Eat small, frequent meals.
  • Drink plenty of water and other liquids to prevent dehydration. People with severe dehydration may need to receive IV fluids.
  • Ask your doctor about changing the schedule or dose of chemotherapy if the diarrhea is caused by chemotherapy and is severe.
  • Ask your doctor about antidiarrheal medications. Octreotide (Sandostatin) can be used to treat diarrhea caused by chemotherapy. No drugs have been approved for preventing diarrhea caused by radiation treatments to the pelvic area, but some are being studied. If diarrhea continues after changes to diet, opioid medications may help to relieve diarrhea.

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