Each person is different, so is their reaction to treatment. Side effects may be severe or mild. Or you may not have any. Talk with your cancer care team about possible side effects before treatment begins.
Chemotherapy can damage the cells lining the intestine. This, in turn, can cause diarrhea (watery or loose stools). Talk with your doctor if you have diarrhea that lasts for more than 24 hours, if you can't keep liquids down for more than 24 hours, if you see blood in your stool, or if you have pain and cramping along with diarrhea. It is important that you replace the water and nutrients you have lost. Your doctor may prescribe a medicine to control your symptoms. If symptoms persist, you may need fluid replacement intravenously (I.V.). It is possible to replace these I.V. fluids on an outpatient basis. When you are having chemotherapy, you should not take any over-the-counter medicines for diarrhea without first talking with your doctor.
Some chemotherapy medicines, such as irinotecan, can cause quick onset of diarrhea that needs immediate care. If that is the case, your doctor will have given you specific directions for how to respond to changes in bowel habits. Make sure you follow your doctor's directions.