Rectal bleeding is a very common symptom or complaint that can be divided into two categories. There is outside (external) bleeding and there is inside (internal) bleeding.
External bleeding comes from outside of the rectum, from the anal skin or anal canal. It looks bright red on the toilet paper; or, if it drips into the toilet bowl, it is always bright red. There is no blood mixed in with the bowel movements. The person has no bloody diarrhea and does not pass any blood clots.
Internal rectal bleeding comes from the rectum or colon, or even from the small intestine or the stomach. This bleeding is associated with blood clots, blood mixed in with bowel movements, dark purple blood, black stools, bloody diarrhea, or bleeding associated with belly pain. Sometimes, the blood is hidden and can only be seen by doing a special hemoccult test. If internal rectal bleeding occurs, the person should be evaluated with a colonoscopy to determine the cause of the bleeding.
Sometimes it is impossible to tell if the rectal bleeding is internal or external and further testing such as colonoscopy must be done.