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Ulcerative Colitis

Medically reviewed by Last updated on Oct 24, 2022.

What is Ulcerative Colitis?

Harvard Health Publishing

Ulcerative colitis is an inflammatory disease. It usually begins in the rectum, then worsens to involve some or all of the large intestine. Ulcerative colitis is a lifelong condition.

Ulcerative colitis may begin with a breakdown in the lining of the intestine. The inside of the intestine, with its digested food, contains trillions of bacteria. Normally, the lining of the intestines keeps these bacteria from causing an infection of the wall of the intestine.

As long as the bacteria are contained, they remain invisible to your immune cells. They do not provoke a reaction. But when the intestine's lining fails, bacteria that usually are harmless can activate your immune system.

Ulcerative colitis is an autoimmune disease. This means that the immune system, which is supposed to attack foreign things that get inside our bodies, instead attacks a part of the body.

In ulcerative colitis, the bowel bacteria provoke the immune system to attack the wall of the intestine itself, injuring the bowel.

There also is evidence that unusually large or small numbers of certain types of bacteria that normally live in everyone's gut can make the gut vulnerable to ulcerative colitis.

Once the bowel inflammation has started, it can continue. It continues even if the immune system stops being exposed to the bowel bacteria.

Ulcerative colitis affects the inner lining of the rectum and colon. This causes the lining to:

  • Wear away in spots (leaving ulcers)
  • Bleed
  • Ooze cloudy mucus or pus

Sometimes, other parts of the body are affected by the inflammation. These include the eyes, skin, liver, back and joints.

Ulcerative Colitis

The disease is not contagious. Contact with another person cannot spread the disease.

Ulcerative colitis usually begins to cause symptoms between the ages of 15 and 40.

Ulcerative colitis substantially increases the risk of colon cancer.


The symptoms of ulcerative colitis vary. Some people with the disease have a burst of symptoms every few months. Others have symptoms all the time. Some, fortunately, have symptoms only rarely.

Typical symptoms include:

  • Cramping abdominal pain, especially in the lower abdomen
  • Bloody diarrhea, often containing pus or mucus
  • Little warning before you need to have a bowel movement
  • The need to wake from sleep to have bowel movements

Ulcerative colitis also may cause:

  • Fever
  • Fatigue
  • Decreased appetite
  • Weight loss
  • Loss of fluids that can lead to dehydration


To confirm a diagnosis of ulcerative colitis, most patients have either flexible sigmoidoscopy or colonoscopy. Both procedures use a small camera and light to view the insides of your large intestine.

A biopsy may be done during either procedure. In a biopsy, small samples of tissue are clipped from the lining of the intestine. They may be examined for signs of inflammation.

Many temporary conditions, such as infections, cause the same symptoms as ulcerative colitis. Therefore, your doctor will want to test your stool for other conditions such as bacterial infections or parasite infections.

Blood tests may also be done to check for anemia (low red blood cell count) or low iron levels. These can occur in ulcerative colitis.

Blood tests may be done to detect inflammation, and to check on your liver. Inflammation of the liver ducts occurs in some people with ulcerative colitis.

Expected Duration

Ulcerative colitis is a lifelong condition, unless the large intestine is surgically removed. Most people with ulcerative colitis do not have their colon removed. That is because their symptoms can be controlled with medication. Or, they only have symptoms once in a while.

In ulcerative colitis, the inflammation is not always active. There can be long breaks between symptoms.

Each time ulcerative colitis acts up, symptoms can last for weeks or months. Often these flare-ups are separated by months or years of good health with no symptoms.

Some people notice that certain foods aggravate their symptoms. By managing their diet, these people can increase the time between flare-ups.


There is no way to prevent ulcerative colitis.

However, some people are able to decrease the frequency of symptoms. They do this by avoiding foods that seem to provoke flare-ups. For some people with ulcerative colitis, this includes spicy foods and milk products.

If you have ulcerative colitis, you can decrease the toll it takes on your body. To do this, eat a well-balanced, nutritious diet—especially when you are not having symptoms such as poor appetite and nausea that make it hard to eat. By doing so, you can decrease complications from malnutrition, such as weight loss or a low blood count.

Ulcerative colitis increases your risk of colon cancer. People with extensive inflammation in the whole colon have the highest risk. It is important to have your colon checked frequently for early signs of cancer. Ask your doctor how often you should have a colonoscopy.

Poor nutrition or the effect of colitis medicines can lead to osteoporosis. This disease weakens bones and can cause bones to break. Osteoporosis can be prevented with medicines, adequate exercise, calcium and vitamin D. If you have ulcerative colitis, discuss osteoporosis with your doctor.



Medications are very effective for improving the symptoms of ulcerative colitis. Most of the medications used work by preventing inflammation in the intestine.

A group of anti-inflammatory medicines called aminosalicylates are usually tried first. These medicines are chemically related to aspirin. They suppress inflammation in the gut and in joints. They are given:

  • By mouth, as pills
  • Directly into the rectum, as a suppository. A suppository is a waxy capsule.
  • As an enema (liquid that is squeezed from a bag or bottle into the rectum)

Aminosalicylates clear up symptoms in most people. But you may need to receive treatment for three to six weeks before you are free of symptoms.

Other, more powerful anti-inflammatory medicines are prescribed when the disease is very active or it cannot be controlled with an aminosalicylate. Often, the first choice of an anti-inflammatory drug is a corticosteroid, such as prednisone or a steroid foam.

When these medications are not effective, one or more other immune suppressing treatments may be recommended. These may include one or more of the following:  azathioprine, cyclosporine, an anti-tumor necrosis factor medication (such as infliximab), vedolizumab, ustekinumab, or tofacitinib.

Doctors are always concerned about side effects from the anti-inflammatory and immune suppressing medicines, especially the increased risk of infection. So the goal is to reduce the dose and then stop the anti-inflammatory drug once the disease is under control.

You may also be given medicines to decrease painful spasms of the colon.

When symptoms are severe or when diarrhea causes dehydration, you may need to be hospitalized to receive intravenous fluids, steroids, antibiotics, and sometimes intravenous nutrition while the colon recovers.

Surgery is used in people who have:

  • Severe symptoms that are not controlled by medicines
  • Unacceptable side effects from medicines
  • A very high risk of colon cancer because of extensive inflammation in the whole colon

After some surgeries, bowel movements will have to leave the body through an opening in the abdominal wall. This opening is called a stoma. The stoma replaces the function of the rectum. It may be connected to a drainage bag. The stoma may be used temporarily or permanently.

Newer surgical techniques allow many patients to keep the muscular layer of the rectum while still removing the rectal lining. This type of surgery has a cosmetic advantage. And, it allows bowel movements to pass through the rectum. Bowel movements are near normal, except that they are more frequent and contain more liquid.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

When To Call A Professional

New or changing symptoms often mean that additional treatment is needed. People who have ulcerative colitis should be in frequent contact with their physicians.

Common symptoms that require a doctor's immediate attention are:

  • Fever, which could indicate infection or a ruptured intestine
  • Heavy bleeding from the rectum

A serious, but uncommon, complication is called toxic megacolon. This results when the colon inflammation is so severe that it stops the colon's motion. Megacolon causes the abdomen to swell. This can cause vomiting or severe abdominal pain and bloating. Megacolon requires emergency treatment, often surgery.


Ulcerative colitis can affect people very differently. Many people have only mild symptoms. They do not require continuous treatment with medicines.

Others might require multiple medicines or surgery. Unless it is treated with surgery, this disease is a lifelong condition.

Ulcerative colitis requires people to pay special attention to their health needs. They must also seek frequent medical care. But most people can have normal jobs and productive lives.

It can be helpful for a person newly diagnosed with ulcerative colitis to join a support group of other people with the disease.

Additional Info

Crohn's and Colitis Foundation of America

National Institute of Diabetes and Digestive and Kidney Disorders

Learn more about Ulcerative Colitis

Treatment options

Care guides

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.