This differs from ulcerative colitis , which is limited to the colon and rectum. Microscopic colitis , which includes lymphocytic and collagenous colitis , also can cause ongoing watery diarrhea, but it is different from ulcerative colitis . Colitis is inflammation of the large intestine that can be acute or chronic. Learn about the different types of colitis , such as ulcerative colitis , Crohn's disease, infectious colitis and more, and how they are diagnosed and treated. Most of the time, the cause of colitis is not known. Causes of colitis include: Infections caused by a virus or a parasite Food poisoning due to bacteria Crohn disease Ulcerative colitis Lack of blood flow to the colon (ischemic colitis ) Past radiation to the colon (radiation colitis and strictures) Necrotizing enterocolitis in newborns Pseudomembranous colitis caused by Clostridium difficile infection (now called Clostridiodes difficile)
