A long-term condition where the large bowel (colon and rectum) becomes inflamed. It cannot currently be cured, but treatment can control symptoms and keep people in remission. Community experiences, not medical advice.
Call 999 or go to A&E if (NHS):
Do not drive to A&E. Ask someone to drive you or call 999 and ask for an ambulance. Bring any medicines you take with you.
Ask for an urgent GP appointment or get help from NHS 111 if you have symptoms of ulcerative colitis and (NHS):
If you've been diagnosed with ulcerative colitis and are having a severe flare-up, you can also contact your care team or IBD advice line. Hospital IBD advice lines and the Crohn's & Colitis UK helpline (0300 222 5700) are not emergency services (Crohn's & Colitis UK helpline; IBD Services Map).
See a GP if you think you have symptoms of ulcerative colitis (NHS).
If you have thoughts of suicide or self-harm, call NHS 111 or go to your nearest A&E. You can also call Samaritans on 116 123, any time of day (Crohn's & Colitis UK).
Ulcerative colitis (UC) is a long-term condition where the large bowel (colon and rectum) becomes inflamed. It cannot currently be cured, but treatment can control symptoms and keep people in remission (NHS; Crohn's & Colitis UK). It is one of the main types of inflammatory bowel disease (IBD).
UC always starts at the rectum and can spread continuously up the colon; it affects the inner lining of the bowel. Crohn's disease, the other main type of IBD, can affect any part of the gut, often in patches (Crohn's & Colitis UK; NHS).
UC is described by how much of the bowel is inflamed: proctitis (rectum only), proctosigmoiditis or left-sided colitis, and extensive colitis (pancolitis). The extent matters because it changes which form of treatment is used. Crohn's & Colitis UK says about 1 in 10 people with proctitis later develop colitis affecting most of the colon (Crohn's & Colitis UK; ACG 2025).
Microscopic colitis is a different condition: it causes ongoing watery diarrhoea, and it is diagnosed by looking at a tissue sample (biopsy) from the colon under a microscope — the bowel usually looks normal during a colonoscopy (Crohn's & Colitis UK).
Symptoms include diarrhoea (often with blood or mucus), needing to poo urgently or often, tummy pain, tiredness and weight loss. Symptoms come and go as flare-ups and remission. UC can also affect the joints, eyes, skin and liver (NHS; Crohn's & Colitis UK).
UC affecting more than the rectum raises bowel-cancer risk, so regular screening colonoscopies are offered; UC limited to the rectum (proctitis) does not (BSG; NICE; Crohn's & Colitis UK). The British Society of Gastroenterology suggests a risk-assessment colonoscopy about 8 years after symptoms began (BSG 2025); NICE CG118 uses 10 years (NICE CG118). People who also have primary sclerosing cholangitis (PSC), a liver condition linked to UC, are offered colonoscopy from diagnosis (BSG 2025). Crohn's & Colitis UK has more on bowel cancer risk in IBD.
Fertility is usually unaffected when UC is controlled; a flare during pregnancy raises the risk of early birth and low birth weight, so it is best to plan pregnancy with the IBD team, ideally in remission. Most UC medicines can be continued, but some must not be used in pregnancy (for example methotrexate, JAK inhibitors and S1P modulators). Sulfasalazine can lower sperm count, reversibly, and pouch surgery may reduce fertility (Crohn's & Colitis UK; NICE NG130; ECCO 2023; BSG 2025).
UC is more common in people who have never smoked or who have stopped smoking, and it is not clear whether smoking makes existing UC better or worse. Smoking seriously harms overall health, and nobody should start smoking or use nicotine products to try to treat or prevent UC (Crohn's & Colitis UK; NHS). Everyone with UC is advised not to smoke; if you smoke, your IBD team or NHS stop smoking services can help (Crohn's & Colitis UK).
UC is managed by a specialist IBD team, guided in the UK by the NHS, NICE NG130 and the British Society of Gastroenterology, alongside European (ECCO 2026) and US (ACG 2025, AGA) guidelines.
Specialist care: People with UC should be looked after by a specialist IBD team; many hospitals run IBD advice lines (usually IBD nurses) for flares, which are not for emergencies (NICE NG130; ECCO 2026; Crohn's & Colitis UK).
Day-to-day: Take your medicines even when you feel well; keep a food and symptom diary; drink plenty of fluids if you have diarrhoea; eat a balanced diet; exercise regularly; try ways to manage stress; keep to 14 units of alcohol a week or less; go to screening appointments when invited; and know how to reach your IBD team or advice line (NHS; Crohn's & Colitis UK; Crohn's & Colitis UK flare-ups). Have any vaccinations you're offered — some UC medicines make infections more likely (NHS).
These are cautions, not approaches people discuss:
Anecdotal themes:
National Institute for Health and Care Excellence. Covers inducing and maintaining remission by disease extent, acute severe UC, surgery and patient information.
View guidelineMoran GW et al. Gut 2025;74(Suppl 2):s1–s101. doi:10.1136/gutjnl-2024-334395.
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View via DOIThe information provided is for educational purposes only and is not intended as a diagnosis, treatment, or substitute for professional medical advice. Always consult with a qualified healthcare provider about your specific situation. Call 999 or go to A&E for severe tummy pain, non-stop bleeding from your bottom, a lot of blood or large blood clots when you poo, or vomiting blood; for a severe flare-up, contact your care team or IBD advice line, ask for an urgent GP appointment, or get help from NHS 111.