Crohn's Disease and Ulcerative Colitis are similar — so similar that they're often mistaken for one another. Both diseases cause inflammation of the lining of your digestive tract, and both may result in severe bouts of diarrhoea and abdominal pain.2
Crohn's disease can occur anywhere in your digestive tract, often spreading deep into the layers of affected tissues.
Ulcerative Colitis, on the other hand, usually affects only the innermost lining of your large intestine (colon) and rectum.