Ulcerative colitis (UC) is a long-term inflammatory bowel disease (IBD) that can affect stool texture, composition, and frequency. Diarrhea and blood in stool are UC symptoms, but constipation may also occur.

In people with UC, the large intestine, or colon, becomes inflamed to the point that severe ulcerations can develop. These ulcers can also develop in the rectum.

The type of stool symptoms people experience will depend on the location of the inflammation and ulceration within the colon.

This article outlines the various UC stool symptoms, along with the possible treatment options.

Doctors may use the Bristol Stool Chart to help a person recognize healthy bowel movements or identify possible problems.

The stool changes that occur in UC are due to inflammation. Over time, inflammation can damage the lining of the large intestine.

People with UC may experience painful abdominal cramps and a frequent need to empty their bowels.

According to the Crohn’s and Colitis Foundation, a person with UC may also experience the following symptoms:

  • diarrhea
  • stool containing mucus or blood
  • pain in the abdomen

Crohn’s & Colitis UK reports that roughly 70% of people with inflammatory bowel disease (IBD) have also experienced bowel incontinence — the unintended passing of stool, or “having an accident.”

Also, some people with IBD experience constipation instead of diarrhea.

Learn more about the common stool changes below:


Diarrhea occurs when the intestinal wall becomes inflamed and the muscles in the colon contract more frequently. This pushes stool through faster, and the colon loses its ability to absorb water from waste.

When waste retains too much water, it results in loose stool.

Blood in stool

Often, the ulcers that form within the lining of the colon can bleed, resulting in bloody stool.

A person who regularly loses a lot of blood in their stool may develop anemia.


Although most people with UC have loose stool, some may also experience constipation.

Constipation is more common among people with proctitis, in which inflammation and ulceration affect only the rectum.

Symptoms of constipation include:

  • reduced frequency of bowel movements
  • harder stool
  • difficulty passing stool
  • bloating
  • cramping
  • feeling that the bowels are not empty even after a bowel movement

Bowel incontinence

Most people with UC tend to experience bowel incontinence during a flare-up of the disease.

However, according to Crohn’s and Colitis UK, around 1 in 10 people with IBD who experience bowel incontinence will do so during a period of disease remission.

The following factors may cause bowel incontinence:

Increased sensitivity of the rectum

As the rectum becomes inflamed, it will also become more sensitive. Heightened sensitivity in the rectum can cause it to become more active, pushing out stool as soon as it arrives.

IBD surgery

People with severe UC may have surgery to remove all or part of the large intestine.

In “pouch surgery,” the surgeon replaces the colon with an internal pouch. Some people who undergo this procedure may develop bowel incontinence.

Severe constipation

A buildup of stool can irritate the lining of the rectum, causing an overproduction of mucus.

If the rectum constantly contains stool, the anus muscles relax, allowing the mucus to leak out.

The following UC treatments reduce inflammation that leads to stool symptoms:

  • Aminosalicylates: These drugs target inflammation in the lining of the colon.
  • Corticosteroids: These are powerful, fast-acting anti-inflammatories used to treat UC flare-ups.
  • Immunomodulators: These drugs regulate the immune system.
  • Biologics: These drugs target inflammation in the gut.

Treating diarrhea

Experts may recommend that people with IBD avoid taking antidiarrheal medications.

Antidiarrheal drugs can increase the risk of a complication called toxic megacolon, in which digestive gases become trapped in the colon, causing it to swell. In some cases, this can be fatal.

The safest way to treat diarrhea is to make dietary changes. Many people with UC experience diarrhea after eating specific foods.

Keeping a food diary along with a daily record of stool symptoms can help people identify and eliminate these trigger foods.

Reducing blood in stool

A recent study suggests that prebiotics and some probiotic supplements may help reduce bloody stool and other symptoms of UC by improving the gut microbiome. Effectiveness can depend on the probiotic strain.

If a person frequently has bloody stool, a doctor may prescribe iron supplements to help prevent anemia.

Treating constipation

The International Foundation for Gastrointestinal Disorders (IFFGG) recommends the following treatments for mild constipation:

  • drinking plenty of fluids
  • eating fibrous foods such as uncooked fruits and vegetables
  • eating whole grain bread and cereals

However, many people with UC find that fibrous foods and whole grains trigger other symptoms, so keeping a food diary can help them identify which foods cause which symptoms.

Other methods for relieving constipation include:

  • Squatting while having a bowel movement: Sitting with the knees higher than the hips when using the toilet can help align the rectum, making stool easier to pass.
  • Exercising: Exercise helps speed up stool movement through the colon.
  • Taking laxatives: Doctors may recommend osmotic laxatives for people with IBD. These increase water availability in the colon, which helps soften stool.

However, it is important that people with UC talk with a doctor before taking laxatives, as these medications can increase gas and stomach cramps.

Managing bowel incontinence

Many people who experience bowel incontinence find it difficult to discuss the issue with a doctor.

However, a doctor may be able to identify the underlying cause of a leaky bowel and can offer advice on how to manage this symptom.

Some suggestions for managing bowel incontinence include:

Bowel retraining

People who experience a sense of urgency may benefit from delaying bowel movements. This technique is called bowel retraining.

Although bowel retraining may be difficult at first. Over time, it can help build strength and control over the rectum and sphincter muscles.

Pelvic floor exercises

The pelvic floor muscles support the pelvic organs, which include the bladder and bowel, as well as the uterus in women.

Pelvic floor exercises can help strengthen the muscles around the anus, reducing incontinence. To find the pelvic floor muscles, imagine stopping a urine stream or practice this while urinating.

To perform pelvic floor exercises, contract and hold the pelvic floor muscles for a count of 3, and then relax the muscles, while slowly counting to 3. Avoid pushing out the muscle during the relaxation stage.

Repeat this 15 times to complete one set of exercises. Aim to complete three sets each day.

UC can also cause other symptoms. The Crohn’s and Colitis Foundation notes that people with UC may also experience:

  • loss of appetite
  • weight loss
  • abdominal cramps
  • anemia
  • eye issues, such as redness or vision changes
  • mouth sores
  • joint pain and swelling
  • skin problems, such as rashes or sores

Treatment may also cause side effects, though this can depend on the specific medication.

People with UC may experience uncomfortable, inconvenient, and sometimes distressing stool symptoms. These can greatly affect a person’s quality of life.

However, treatment can help those with UC experience fewer and less severe symptoms.

It is recommended that a person discuss the options with a doctor to establish the most effective treatment plan.

Read the article in Spanish.