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Ulcerative colitis: the signs, the tests, treatment, and day to day
For anyone who has had diarrhea with blood or mucus for weeks; for anyone just told they have ulcerative colitis, or in the middle of a flare; for anyone whose doctor is talking about a new medicine or surgery; and for the people who love them. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, part of the NIH) says it is a chronic disease in which abnormal reactions of the immune system cause inflammation and ulcers on the inner lining of the large intestine, that it is a kind of inflammatory bowel disease, and that most people have flares with periods of remission between. This page passes on, by name, what NIDDK says: the signs, flares, and when it cannot wait; who gets it and what can come with it; the history, the exam, blood and stool tests and colonoscopy; the kinds of medicine, pain relief and surgery; and food, colorectal cancer checks and bones. It builds the words to say to a doctor, and prints a card to carry.
Right now
- A lot of blood from the rectum, fainting, or severe belly pain with a hard, swollen belly? NIDDK names severe rectal bleeding, perforation and toxic megacolon as complications that can be life-threatening and need a hospital or emergency surgery. Call 911 (ours). Do not drive yourself.
- More than 10 bloody bowel movements in a day, often with fever or a fast heartbeat? NIDDK calls this extremely severe (fulminant) ulcerative colitis, most often treated in a hospital. Call your doctor right away; if you cannot reach anyone, go to an emergency room (ours).
- Blood in your stool for the first time? See a doctor soon, even if it stops (ours).
- It is all too much, or you are thinking of ending your life? Call or text 988, any hour (ours).
More help
- The belly, on this site: Crohn’s disease · Irritable bowel syndrome · GI bleeding · Colon polyps · An upset stomach: find the right page.
- What can come with it, as NIDDK names it: Anemia · Osteoporosis · Arthritis · Primary sclerosing cholangitis · When you or someone you love has cancer.
- Day to day: My medicines list · Symptom diary · Get ready for your appointment.
- Care and costs: When you can’t afford your medicine · When you need a doctor and can’t pay · When a medical bill is too much.
- In a crisis: Help right now (988, 911). All our free tools.
An upset stomach, and not sure this is the right page? The pages on this site for throwing up, diarrhea, heartburn and constipation, on one list.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 17, 2026 on NIDDK’s Ulcerative Colitis pages (NIH): the overview, Definition & Facts, Symptoms & Causes, Diagnosis, Treatment and Eating, Diet, & Nutrition, all last reviewed in September 2020. NIDDK has no Spanish version of these pages; our Spanish page is our own translation. NIDDK names the medicines only by kind, and so do we; newer medicines may exist since 2020. One line on NIDDK’s Definition & Facts page (yearly colonoscopy with “primary biliary cholangitis”) sits oddly beside the page’s own naming of primary sclerosing cholangitis as the cancer risk, so we quote it as written and say to ask. Ours: 911 for a lot of blood from the rectum, fainting, or severe pain with a hard, swollen belly; calling the doctor right away for many bloody bowel movements, fever, a racing heart or signs of dehydration, and an emergency room if no one answers; seeing a doctor soon for blood in the stool or diarrhea that lasts; bringing a list of everything you take; keeping a diary; writing down the date of your next colonoscopy; the card; 988 when it is too much; health centers when money is tight; and the order of the steps. What we left out: medicine names, brands, doses, research studies, and clinical pages for providers. This page saves nothing and loads no trackers.