An exact cause of ulcerative colitis is unknown as research is going on ulcerative colitis causes. Perversely diet and stress are suspected of the causes of ulcerative colitis but due to lack of evidence, we cannot say that stress and diet are responsible for ulcerative colitis. Immune system malfunction is one possible cause for ulcerative colitis. Where abnormal immune response causes the immune system to attack cell of the digestive tract. Heredity also plays a role in the development of ulcerative colitis.