Ulcerative colitis usually causes diarrhea, which may be watery and appear fluffy, mushy, or bloody. You may also experience constipation, which may present as small, hard stool lumps.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that causes inflammation and ulcers along the lining of the colon and rectum. UC can affect all or part of the colon.

The location and severity of inflammation may determine the type, frequency, and consistency of your stools.

Keep reading to learn more about how UC can affect your stools.

The primary symptom of UC is diarrhea, which may contain blood or mucus. The severity of diarrhea and bloody stools will depend on the degree of inflammation and ulceration in your colon.

The Bristol Stool Chart may help you identify the type of stool you have by examining its appearance and texture.

According to Crohn’s and Colitis UK, diarrhea associated with UC may have a loose, fluffy, or watery consistency, mainly consisting of liquid. The Bristol Stool Chart shows these as types 6 and 7.

Some people with UC may also experience constipation, known as proximal constipation or ulcerative colitis-associated constipation (UCAC).

Constipation may present as small, hard, and lumpy pieces of stool that are hard to pass. This is types 1 and 2 on the chart.

Although the Bristol Stool Chart may provide insight into the type of stool you’re passing, the United Kingdom’s National Health Service (NHS) notes the importance of getting immediate medical attention if you experience bloody, black, or tarry stools.

Most people with UC experience diarrhea, which is when you pass loose and watery stools more frequently than usual.

However, some people with UC may also experience constipation. According to the NHS, this is when you pass fewer than three stools in 1 week.

Crohn’s and Colitis UK also notes that up to 7 out of 10 people with UC experience bowel incontinence or urgency.

Bowel incontinence is when you pass a stool without meaning to. Urgency is when you experience the sudden urge to pass a stool. For instance, you may feel like you have to run to the washroom.

Consider speaking with a doctor if you experience changes in your bowel habits. They could help identify the underlying cause and modify your treatment plan.

Changes in stools may be directly related to how UC affects your colon and rectum.

In UC, the immune system attacks healthy cells in your digestive tract, increasing white blood cells in the colon and rectum. Repeated attacks lead to chronic inflammation.

According to Crohn’s and Colitis Canada, chronic inflammation may prevent your intestines from fully absorbing fluids. This may cause extra fluid in the intestines, resulting in diarrhea and more frequent bowel habits.

When inflammation destroys the cells lining your colon, sores or ulcers can develop. These ulcers can bleed and produce pus, resulting in bloody diarrhea.

Inflammation may also impact how frequently your colon contracts and empties itself, leading to frequent diarrhea and urgent bowel movements.

Some people with UC also have constipation, but it isn’t as common as diarrhea.

Constipation may occur due to fecal impaction, which is when stool accumulates and gets stuck in the colon. It may also occur if inflammation is limited to the rectum (ulcerative proctitis) or affects the gastrointestinal muscles and cells responsible for digestion (enteric nervous system).

Other symptoms of ulcerative colitis

In addition to stool-related symptoms, other symptoms of ulcerative colitis may include:

Stopping inflammation is key to managing bloody stools and other UC symptoms. Less inflammation greatly reduces the risk of ulcers, which could help prevent bleeding.

A healthcare professional will help develop a treatment plan to reduce inflammation and keep your symptoms in remission. This may include:

  • medications, including aminosalicylates, immunosuppressants, corticosteroids, and biologics
  • dietary changes, such as avoiding trigger foods and taking probiotics
  • stress relief, such as exercising, doing yoga, using a food journal, and listening to music

If you have diarrhea, ask a doctor about taking an antidiarrheal medication.

The only cure for ulcerative colitis is colectomy, which is a surgery that involves removing part of or all of your large intestine. However, it’s important to note that you may have complete remission and become asymptomatic on medical therapies like biologics or advanced oral therapies.

UC is a chronic health condition that may cause frequent diarrhea, bloody stools, or even constipation.

If left untreated, UC can damage your intestinal tract and increase your risk of developing colon cancer. Unmanaged UC can also interfere with your quality of life, especially if your stools are bloody, unpredictable, and urgent.

Many treatment options are available to help you live more comfortably with UC. Talk with a doctor about what might work best for you.