What Is Ulcerative Colitis? Symptoms, Causes, Diagnosis, and Treatment

Medically Reviewed

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) in which the lining of the large intestine (colon) becomes inflamed.

The colon then develops ulcers (open sores) that produce blood, pus, and mucus.

The small intestine is rarely affected.

The combination of inflammation and ulcers often causes abdominal discomfort, frequent bowel movements, and bloody stools, according to the Crohn’s and Colitis Foundation.

There are several subtypes of ulcerative colitis, which are named according to the part of the colon affected:

  • Ulcerative proctitis, which affects only the rectum
  • Proctosigmoiditis, which affects the rectum and lower segment of the colon (sigmoid colon)
  • Left-sided colitis, which affects the rectum, sigmoid colon, and descending colon up to the sharp bend near the spleen
  • Pan-ulcerative or total colitis, which affects the entire colon, according to the Mayo Clinic.

Common Questions & Answers

What are the symptoms of ulcerative colitis?
The symptoms of UC usually develop gradually and can include abdominal pain, frequent bowel movements, and bloody or pus-filled diarrhea. You may experience weight loss, poor appetite, nausea, fatigue, fever, and anemia. Your symptoms may come and go, and periods without active disease, known as remission, can last months or years.
What should I do during a flare-up?
Treatment by a doctor is essential when you're experiencing a UC flare. But there are some things you can do at home to reduce discomfort: Follow a low-residue diet to give your colon a rest, and use sanitary wipes or sitz baths to soothe a sore behind. It's also important to develop stress management techniques, like yoga or meditation.
What can I eat if I have UC?
Maintain a healthy diet full of lean proteins, fruits, vegetables, and fiber if you have UC. Avoid fatty, spicy foods, or anything that you've identified as a trigger food. (Lactose also tends to cause problems for people with IBD.) If you don't yet know what foods can trigger a flare, it might help to keep a food diary to track what you eat.
How can I treat inflammation naturally?
There are a few evidence-based natural remedies that can help those with ulcerative colitis find relief, like exercising, reducing stress, and consuming a diet rich in soluble fiber. Mind-body practices, like tai chi, qigong, meditation, and yoga, may reduce stress and inflammation in the body.

How Do I Spot the Signs and Symptoms of Ulcerative Colitis?

The most common symptoms of ulcerative colitis are abdominal pain and diarrhea, which often contains blood or pus.

Symptoms of the disease typically develop gradually and come and go.

Periods without active disease — known as remission — may last for months or even years.

Over time, ulcerative colitis can progress to cover more of the colon. This typically leads to more severe disease and greater symptoms.

If left untreated, UC can also lead to a number of complications, including:

Learn More About Ulcerative Colitis Symptoms

What Are the Causes and Risk Factors of Ulcerative Colitis?

Ulcerative colitis is believed to be caused by an abnormal response by your body’s immune system.

Your immune system is supposed to defend you against harmful invasive bacteria and viruses. But in some people, the immune system mistakenly attacks the body’s own tissue.

In ulcerative colitis, this may happen when the body mistakes food and helpful bacteria for harmful substances. It may also come about when the body doesn't turn off its response to fighting an infection.

Either way, the immune system sends white blood cells to the lining of the colon, where they cause inflammation and ulcers, according to the Crohn’s and Colitis Foundation.

Experts believe that ulcerative colitis develops because of a combination of environmental factors and genetic predisposition.

While a specific cause is unknown, diet and stress may aggravate the condition, according to the Mayo Clinic.

For example, one study published in April 2021 in Frontiers in Immunology found that a high intake of trans fats — found in many processed foods — increases intestinal inflammation.

A high intake of omega-3 fatty acids may lower the risk of the condition, according to a review published in February 2021 in Frontiers in Immunology.

Fatty cold-water fish — such as mackerel, tuna, salmon, sardines, and herring — are rich sources of omega-3 fatty acids.

How Is Ulcerative Colitis Diagnosed?

To diagnose ulcerative colitis, your doctor will first take a complete medical history and rule out other possible causes of your symptoms.

This will be done with a combination of your history of symptoms, lab tests, imaging scans, and a view of the inside of your colon using a flexible tube and camera (colonoscopy or sigmoidoscopy).

How Long Will Ulcerative Colitis Symptoms Last?

A flare is a period of time in which symptoms of ulcerative colitis are severe. Generally speaking, flares can last for days or even weeks, although ulcerative colitis is experienced differently from person to person, and duration of symptoms varies greatly for each individual.

People living with ulcerative colitis typically experience periods of both active disease, or flare-ups, and remission, when there are few or no symptoms.

The goal of treatment is to achieve remission.

How Is Ulcerative Colitis Treated?

Medications are the main treatment for ulcerative colitis. Other treatment options include dietary changes and surgery, if necessary.

Drugs for ulcerative colitis work by reducing inflammation in your colon.

Some drugs are commonly used for maintenance therapy — to help you stay in remission — while others are used to treat disease activity during flares. You’re likely to need a combination of drugs for optimal treatment.

Surgery may be necessary if your body isn’t responding well to drugs, or if you have severe complications that require urgent treatment.

It’s most common to remove the entire rectum and colon if ulcerative colitis requires surgery, but more conservative approaches may also be considered.

Learn More About Treatment for Ulcerative Colitis

What Are the Medication Options for Ulcerative Colitis

There are a few types of drugs used to treat ulcerative colitis.

Aminosalicylates are typically the first kind of drug prescribed for ulcerative colitis. They work by reducing inflammation directly in your digestive tract and can be taken on an ongoing basis.

Corticosteroids — also known simply as steroids — are used to treat disease flares. Most drugs of this type work by suppressing the entire immune system, so they can have severe side effects and shouldn’t be taken for long periods.

Immunomodulators limit inflammation at its source in the immune system and are usually used only when aminosalicylates and steroids aren’t enough.

Biologics are the newest type of drug for ulcerative colitis and tend to be used only when other treatments haven’t been effective.

Other drugs for ulcerative colitis may include antibiotics and certain pain relievers.

Learn More About Medications for Ulcerative Colitis

What Should You Eat When You Have Ulcerative Colitis

When it comes to food, there’s no known dietary cause of ulcerative colitis, but different foods may aggravate or help limit symptoms of the disease.

You’re more likely to need to change your diet during periods of active disease (flares), when eating soft, bland foods can help limit symptoms like cramping and diarrhea.

During flares, you may also want to avoid or limit high-fiber and high-fat foods, as well as caffeine, alcohol, dairy products, and spicy foods.

If you’re losing nutrients and water in your diet due to diarrhea, you may need to focus on increasing your fluid intake and getting enough calories, protein, vitamins, and minerals from foods or supplements.

Learn More About Diet and Ulcerative Colitis

Research and Statistics: How Many People Have Ulcerative Colitis?

Ulcerative colitis affects as many as 900,000 Americans, according to the Crohn's and Colitis Foundation.

Symptoms of the condition most often start between ages 15 and 30, with most people diagnosed in their mid-thirties. There’s also a peak between the ages of 50 and 70, according to MedlinePlus.

People of European descent have a higher risk of developing ulcerative colitis than do those of African or Hispanic descent.

People of European Jewish descent have an especially high risk.

Ulcerative colitis tends to run in families, affecting men and women equally overall. But older men are more likely to develop it than older women, according to the Crohn’s and Colitis Foundation.

What Other Conditions Are Related to Ulcerative Colitis

Ulcerative colitis is a type of inflammatory bowel disease (IBD), but it's not the same as irritable bowel syndrome (IBS).

Although the disorders share some of the same symptoms, such as abdominal pain and diarrhea, inflammation and ulcers do not occur with IBS.

Another disease often mentioned alongside ulcerative colitis is Crohn’s disease. Ulcerative colitis and Crohn’s are different types of IBDs that affect the digestive tract in different ways.

There are some common symptoms between the two conditions, but the overall pattern of symptoms tends to be different for each.

While diarrhea and rectal bleeding are more common in ulcerative colitis, Crohn’s disease more often causes severe abdominal pain, nausea, weight loss, and vomiting.

Ulcerative colitis is limited to the lining of the large intestine (colon), whereas Crohn’s disease can affect the entire digestive tract — from your mouth to your anus — and isn’t limited to the inner part of the intestines.

Learn More About the Differences Between UC and Crohn’s

Ulcerative Colitis Resources We Love

Favorite Orgs for Essential UC Info

Digestive Disease Week (DDW)

Each year, Everyday Health editors attend DDW, the world’s largest gathering of physicians, researchers, and industry in the fields of gastroenterology, hepatology, endoscopy, and gastrointestinal surgery.

Crohn’s and Colitis Foundation (CCF)

CCF is considered the leading nonprofit organization dedicated to finding the cure for UC and Crohn’s. The organization is at the forefront of IBD research and works to educate, empower, and support individuals afflicted with these diseases. Find your local chapter by visiting the CCF website.

American Society of Colon and Rectal Surgeons

This society, made up of more than 3,000 colon and rectal surgeons, is dedicated to advancing and promoting the science and practice of treating patients with diseases and disorders affecting the colon, rectum, and anus. Although it is mostly geared toward professionals in the field, the website has an educational library with videos and resources for finding a surgeon.

Benaroya Research Institute, Virginia Mason

This research institute at Virginia Mason in Seattle is one of the few establishments devoted to finding the causes of autoimmune diseases like UC and their cures. Benaroya has already helped advance research in more than 80 diseases of the immune system. The autoimmune life blog provides information on community events and personal stories from patients living with an autoimmune disease.

Favorite Ulcerative Colitis Blogger


Sam Cleasby created her blog in 2013 to raise awareness of IBD and her struggles with self-esteem. Cleasby also has a radio show on BBC Radio Sheffield where she shares about modern family life, including relationships, disability, nutrition, and kids. You can subscribe to her blog via email or follow her on Facebook or Twitter.

RELATED: The Pros and Cons of Opening Up About Ulcerative Colitis Online

Favorite Resource for Diet Advice

'Crohn’s and Colitis Diet Guide'

This book by A. Hillary Steinhart, MD, provides dietary strategies and recipes to help manage inflammatory bowel disease. The head of the combined division of gastroenterology for Mount Sinai Hospital and the University Health Network in Toronto’s Mount Sinai Hospital, Dr. Steinhart worked with the clinical dietitian Julie Cepo to offer well-researched dietary advice for people to maintain health during flare-ups as well as periods of remission. The book is packed with 150 recipes, from risotto to stew, to help anyone with IBD eat well and prevent malnutrition.

'Against All Grain'

Doctors assured Danielle Walker that her diet was not a factor in her ulcerative colitis flares. But after years of suffering and multiple hospitalizations, Walker realized she needed to make dietary changes. At the two-year remission mark, the mom, wife, and self-trained chef began blogging about her experience and sharing recipes to help others struggling with IBD. You can buy Walker’s cookbooks on her website, which is loaded with nutritional resources including a blog and videos.

Favorite Apps

Oshi Health

This all-in-one app helps you track symptoms and general information about sleep, stress, diet, and fitness, which you can share with your doctor. You can also read doctor-approved articles or ask questions directly to medical experts.

For more of our favorite ulcerative colitis apps, check out 5 Phone Apps for People with UC.

Favorite Retreats

Camp Oasis

Over a decade ago, the Crohn’s and Colitis Foundation established a coed residential summer camp to enrich the lives of children living with IBD. The camp is offered in most major regions nationwide as a way for adolescents living with IBD to see that they are not alone, try their hand at new sports and activities, and create friendships with people who truly understand them.

Ages vary by camp location. To find a camp near you, please visit the Crohn's and Colitis Foundation website.

Girls With Guts

What started as a weekend get-together among five IBD bloggers has grown into a worldwide support network of women living with inflammatory bowel disease. Group members share stories and experiences to help one another gain confidence despite IBD or an ostomy. The organization provides supplies for those in need of help from ostomy surgery, as well as a pen pal program to help women connect, and an annual retreat. Sign up for their newsletter to receive news and updates quarterly.

Ulcerative Colitis and COVID-19

The coronavirus pandemic has forced everyone to take extra precautions when it comes to health and safety. This is especially true for individuals with a compromised immune system. Although research shows that people living with UC are no more susceptible to catching the virus than the general population, organizations including the American College of Gastroenterology and the Crohn’s and Colitis Foundation have issued a number of new guidelines to help limit the spread of the infection. It’s also recommended that people with ulcerative colitis get the COVID-19 vaccine.

There are also a number of resources available to help people with UC manage these difficult times — from medication assistance to virtual therapy for mental health.

Learn More About Ulcerative Colitis and COVID-19

Additional reporting by Jordan M. Davidson.

Editorial Sources and Fact-Checking

  • What Is Ulcerative Colitis? Crohn’s & Colitis Foundation.
  • Ulcerative Colitis. Mayo Clinic. July 28, 2017.
  • Ulcerative Colitis. MedlinePlus. August 14, 2015.
  • Ananthakrishnan AN, Khalili H, Konijeti GG, et al. Long-Term Intake of Dietary Fat and Risk of Ulcerative Colitis and Crohn's Disease. Gut. May 2014.
  • Toxic Megacolon. Johns Hopkins Medicine.
  • Colombel JF, Sandborn WJ, Ghosh S, et al. Four-Year Maintenance Treatment With Adalimumab in Patients With Moderately to Severely Active Ulcerative Colitis: Data From ULTRA 1, 2, and 3. American Journal of Gastroenterology. August 2014.
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