The most common sign is diarrhea with blood or pus in it. If your disease is severe, the urge to empty your colon can also come on fast and furious. Sometimes you may feel like you still have to go even though you just went.
Belly pain from ulcerative colitis can feel crampy, like a charley horse in your gut. It can happen before a bowel movement or while you're going.
Other parts of your body might hurt as well, including your joints or eyes. It also can cause canker sores in your mouth and sores on your skin. You might also get rashes.