THE BASICS: “What is ulcerative colitis?”

Ulcerative colitis (UC) is a long-term (chronic) disease of the innermost lining of your large intestine, which includes your rectum and colon.

UC causes inflammation and sores, called ulcers, in the lining of your large intestine. They may bleed and can harm your digestion by:

  • Damaging your intestinal lining
  • Interfering with its ability to pull fluid away from your stool so it becomes solid before a bowel movement

This results in symptoms that most commonly include:

  • Chronic diarrhea
  • Abdominal pain, cramping, or discomfort
  • Blood or pus in the diarrhea

The severity of UC symptoms can range from mild (four or fewer bowel movements per day, with or without blood) to severe (more than 10 bowel movements per day with severe cramps and constant bleeding).

Additional UC symptoms may include:

  • Anemia (reduction of red blood cells to the point where they cannot deliver enough oxygen to meet the body’s needs)
  • Depletion of body fluids and nutrients
  • Weight loss, loss of appetite, nausea, and/or growth problems (in children) due to chronic colon inflammation
  • Rectal bleeding
  • Fatigue
  • Recurring fevers
  • Skin sores
  • Joint pain

If you are diagnosed with UC, there will be:

  • Times when you have symptoms—which can range from infrequent and mild to continual and severe
  • Remissions (the times when you are symptom-free)
    • Remissions can last from months to years before, inevitably, your symptoms return.

For most people with milder forms of UC, the severity of their symptoms remains about the same with each flare-up.

Colon cancer develops in only about 5 percent of people with UC—most commonly in people with UC of the entire colon over a period of years.

  • The risk for people with UC involving only the rectum and lower colon is about the same as for people without UC.


  • The risk of UC-related colon cancer increases over time and as colon damage worsens.
    • After eight years with UC, you may need a yearly colonoscopy to check for precancerous cells (dysplasia).
    • Surgical removal of the colon eliminates UC-related risk of colon cancer.

UC complications affecting the colon include:

  • Severe bleeding
  • Colon perforation (a hole or tear)
  • Toxic megacolon—rapid and dangerous swelling of the colon

Inflammation from UC may also lead to complications outside the colon, which include:

  • Kidney stones
  • Osteoporosis
  • Arthritis
  • Severe dehydration
  • Inflammation of eyes, skin, and/or joints
  • (Rarely) liver disease

Use of anti-inflammatory medications may improve these conditions as well as UC symptoms.

You’ve learned what UC is and how it may affect you (if you have it). Next step:

  • Getting to know the health professionals who can provide the care you need
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