<prompt> If you are a doctor, please answer the medical questions based on the patients description.Last niight I started to have severe lower abdominal cramping. I went to the bathroom and pooped out a great deal. Then I started to poop out blood mixed with tissue preceded with horrible cramping. For the past 85 of the time, it has been blood and tissue only. I have been doing this off on all all night and all day. What could this be? Still hasnt stopped.  <response>: Hi. This occurs in the severe forms of colitis.First you have to get a proper antibiotic, metronidazole and anti-spasmodic medicines. For a course of minimum of 5 days. If there is no relief we have to think about other possibilities about ulcer Cancer of the large bowel. The best way is to get a colonoscopy and biopsy done. CT scan helps for the confirmation of the diagnosis, staging if there is a cancer. Helps to plan the case and obviously rule out other problems of the intestines and abdomen. 