At times, radiation is used to treat prostate cancer or cancer of the female organs. The rectum resides just behind the prostate in the male and the vagina and uterus in the female, so when radiation hits these organs to eradicate the cancer, it also can affect the bowel wall. Radiation proctitis is really a myriad of new, tiny blood vessels on the surface of the rectum. They are generally weak-walled meaning they can bleed with minimal trauma, resulting in blood in the stool. If the bleeding is severe, anemia or a low red cell blood count can occur. Image 1 is a mild case, showing these tiny blood vessels. Image 2 is severe with many blood vessels seen and actually a bit of bleeding as well. This condition can be treated with laser or other methods to coagulate these blood vessels and stop the bleeding.