Rectal bleeding

  • Inflammation, or swelling, in the lining of the colon can cause bleeding.

  • Bleeding can cause anemia (low blood counts), which can cause tiredness and weakness. Treating the inflammation in the colon and correcting vitamin/mineral deficiencies can make you feel better. Severe bleeding is a rare complication of UC.


  • This happens when the large intestine is unable to absorb fluids because of diarrhea and inflammation.

Changes in bones

  • Some corticosteroid medications taken to treat UC symptoms can cause:

    • Osteoporosis—the loss of bone.

    • Osteopenia—low bone density.

  • A simple imaging test can tell you if you have osteopenia or osteoporosis.

  • Your health care providers will monitor you for bone loss and can recommend calcium, vitamin D supplements and/or medications to help prevent or slow bone loss.

Inflammation, or swelling, in other areas of your body

  • Your immune system can trigger inflammation in your:

    • Joints.

    • Eyes.

    • Skin.

    • Liver.

  • Your health care provider can treat inflammation by adjusting medications or prescribing new medications.

Toxic megacolon

  • This complication occurs when very severe inflammation spreads to the deep tissue layers of the large intestine, causing the colon to dilate. This can put you at risk for severe infection and shock.

  • It can be a life-threatening complication and most often requires surgery.

  • It is a rare complication of UC.

If you think you are having one of these complications of UC, let your health care provider know right away.

Potential signs of complications

  • Inability to drink enough fluid or losing more fluid than taken in.

  • High heart rate.

  • Very low blood counts.

  • Severe, constant pain.

  • High fever.