Diarrhea can be a major problem for cancer patients. Some chemotherapy drugs are notorious for causing diarrhea. These chemotherapy drugs include irinotecan (Camptosar), 5-fu, cetuximab (Erbitux), erlotinib (Tarceva), and capecitabine (Xeloda). Diarrhea can occur with any chemotherapy drug including immunotherapy. Diarrhea associated with immunotherapy is particularly concerning, as it can progress rapidly to severe, even life threatening, diarrhea if not treated aggressively. If you feel weak or dehydrated (dizzy, low blood pressure, marked weight loss) let us know, you will likely need to be seen in the office. We may be able to administer intravenous fluids and keep you out of the emergency room.