Ulcerative colitis is a lifelong condition that turns your immune system against your colon.

Health · Published 3 October 2026 Swipe more like this →

In short: Ulcerative colitis is a chronic inflammatory bowel disease that causes sores and swelling in the lining of the large intestine. While the exact cause remains unknown, it is widely considered an autoimmune condition where the body mistakenly attacks itself, leading to unpredictable flare-ups and potentially serious, long-term health complications.

Ulcerative colitis (UC) is the most common form of inflammatory bowel disease, affecting an estimated one million Americans. While it can manifest at any age, diagnosis is most frequent before age 30, or alternatively, after age 60. The condition is characterized by chronic inflammation and ulcers that typically begin in the rectum and can extend throughout the colon. Unlike Crohn's disease, which may affect any part of the digestive tract in a patchy distribution, UC inflammation is generally continuous and confined to the large intestine.

The disease is driven by an overactive immune response, though researchers have yet to pinpoint a definitive trigger. Genetics play a notable role; individuals with a first-degree relative who has the condition face a higher risk, and up to 20% of patients report a family history of UC or Crohn's. Ethnicity is also a factor, with the highest prevalence observed among white populations, particularly those of Ashkenazi Jewish descent. While diet and stress do not cause the disease, they are recognized as common triggers for symptom flare-ups.

Symptoms range from mild to severe and often include bloody diarrhea, abdominal pain, urgency, and fatigue. Because the condition is systemic, inflammation can spread beyond the colon to affect the eyes, skin, joints, and liver. Long-term complications include anemia, osteoporosis, and an increased risk of colon cancer. While there is no cure, treatment aims to induce and maintain remission through medications such as aminosalicylates, steroids, immunosuppressants, and biologics. In severe cases where medical therapy fails or complications arise, a colectomy—the surgical removal of the colon—may be necessary to eliminate the disease entirely.

General information, not professional advice. Spotted an error? Flag the card or see corrections and complaints.

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