4. Ulcerative colitis
A form of inflammatory bowel disease (IBD), ulcerative colitis typically affects the colon, resulting in bloody diarrhea. “It strikes right at the bottom of the bowel,” explains Dr. Enns. “It’s as if someone has rubbed sandpaper on the lower bowel, resulting in something like road rash. It tends to give diarrhea, with bleeding of varying severity.” People who have ulcerative colitis tend to have diarrhea at night. Dr. Enns says that’s a sign that something serious could be going on, especially if it is accompanied by blood in the stool, or weight loss. Ulcerative colitis should be treated with medication.