One of the more irritating symptoms of ulcerative colitis is constipation. You may experience extended periods of constipation, followed by periods of pain and frequent diarrhea. Ulcerative colitis can appear in many forms, one of which is proctosigmoiditis, and it mainly affects the colon. That’s why it can provoke diarrhea, which may be bloody, as well as other digestive-related ailments. Being constipated means spending lots of time on the toilet, but being unable actually to pass a bowel movement. Different treatments may help reduce constipation, but each person reacts differently to specific therapies.