Surgery on the intestines, abdominal radiation, chemotherapy drugs, and bone marrow transplants can cause diarrhea.  Those taking targeted therapy drugs can also experience diarrhea. However it is usually mild.  Diarrhea caused by antibiotics tends to be more extreme and can even be life threatening.

The inability of intestines to absorb water causes diarrhea.  This may be caused by overly active intestinal muscle or damage to dividing cells lining intestines.

Usually diarrhea will occur within the first few days or week after treatment.  The symptom usually resolves within a few weeks after completion of treatment.  However, bone marrow transplantation may cause diarrhea for up to a week or a few months after treatment.

Diarrhea can be prevented or minimized through changes in diet.  A diet of only clear liquids may help the lining of intestines heal once diarrhea occurs.  Water, apple or cranberry juice, ginger ale, clear broth, popsicles and Jell-O can help.  Foods high in potassium are recommended.  During diarrhea the body loses significant amounts of potassium.  Patients should also avoid dairy products, foods high in fiber, and raw fruits or vegetables.  Spicy, greasy, or fried foods can also make diarrhea worst.

Along with changes in diet, medications are also available to help combat diarrhea.  Fiber supplements may also be helpful.  One should consult a doctor before taking any over-the-counter medications.  Doctors may also prescribe other medications for severe cases.  Stopping treatment maybe needed until diarrhea is more manageable.

Discomfort in rectal area caused by diarrhea may be soothed.  Patients should clean the external rectal area with warm water and soap after bowel movements, soak in warm bath, or use a water-repellant cream.