Ulcerative colitis

Last Updated: July 3, 2026

Key Points

Long-term inflammation of the colon and rectum
Causes small ulcers that can bleed and produce pus
Symptoms include recurring diarrhea, tummy pain, and fatigue
Often diagnosed in people aged 15 to 25 years

Overview

Ulcerative colitis is a chronic condition where the large intestine (colon) and its end part (rectum) become inflamed. Small ulcers can form on the lining of the colon, which may bleed and produce pus, significantly impacting daily life for some individuals. This condition is believed to be autoimmune, meaning the body's immune system mistakenly attacks healthy tissue in the colon. Experts suggest a combination of genetic and environmental factors contribute to why the immune system behaves this way. Treatment focuses on relieving symptoms during flare-ups and preventing their return. This is typically managed with medication, but in some cases, surgery to remove part or all of the bowel may be necessary.

Signs and Symptoms

Recurring diarrhea (may contain blood, mucus, or pus)
Tummy pain
Frequent urge to pass stool
Extreme tiredness (fatigue)
Loss of appetite and weight loss
Painful and swollen joints (during flare-ups)
Mouth ulcers (during flare-ups)
Irritated and red eyes (during flare-ups)

Things That Increase the Risk

Autoimmune condition (immune system attacks healthy tissue)
Genetic factors (family history)
Environmental factors (specific triggers unclear)
Age (most often diagnosed between 15 and 25 years old)
Ethnicity (more common in white people of European descent and black people)

Diagnosis

GP consultation and symptom review
Blood tests
Stool (poo) sample tests
Referral to hospital for further tests, such as a colonoscopy

Treatment & Management

Medications like aminosalicylates (ASAs)
Corticosteroids (steroid medicines)
Immunosuppressants
Hospital admission for severe flare-ups
Surgery to remove part or all of the bowel (colon)
Ileostomy (creating an opening in the abdomen)
Ileoanal pouch (creating an internal pouch)

Prevention

Managing stress to reduce flare-up frequency
Avoiding gut infections when possible
Adhering to prescribed medications to maintain remission
Regular medical follow-ups to monitor the condition
Monitoring for potential complications like bowel cancer

Available Treatments

Explore our range of treatment options for Ulcerative colitis: