Bloating and other symptoms like gas and constipation can be common with ulcerative colitis. Bloating can happen when inflammation and ulcers affect digestion. Dietary changes and medication may help.

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Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that causes inflammation and tiny sores, called ulcers, in the lining of the colon. Inflammation and ulcers may also form in the rectum.

While the cause of UC is not completely known or understood, research suggests that an overreaction of the immune system to a colon infection plays a strong role and may even be a trigger. Genetics, changes in gut microbiota, and environmental factors are also thought to play a part.

UC affects people differently. Some people have chronic diarrhea accompanied by gas and bloating most of the time. Others have constipation which can then cause gas and bloating to occur.

Living with UC can be challenging. Read on to learn why the factors that cause UC can lead to bloating, a common symptom of UC, and what you can do about it.

The inflammation and ulcers that result from ulcerative colitis make digestion difficult. If you’re not digesting food efficiently, a variety of symptoms — including bloating — can occur.

If your stomach is bloated, you may feel pressure or a feeling of tightness in your abdomen. Your stomach may also look or feel full or distended.

Ulcerative colitis symptoms, such as trapped gas, constipation, and diarrhea, can all lead to bloating.

Trapped gas

Bloating is often the result of excess intestinal gas that gets trapped inside your digestive tract.

Gas forms in the colon when bacteria in your microbiome break down and ferment undigested carbohydrates. This gas exits your body through belching and flatulence (farting).

If your body produces too much gas quickly, it may build up in your system without exiting fully.

Trapped gas is a common cause of bloating. It can also cause intense stomach pain.


Constipation occurs when newly digested food and stool remain in your digestive system for an extended period. This gives bacteria additional time to ferment the undigested matter, causing gas and bloating.

The excess burden of food and backed-up stool makes your stomach expand. A sluggish, bloated feeling and discomfort are common results. Extra digestive contents also take up room in your colon, making it harder to expel gas.

UC constipation also gives stool time to dehydrate, causing dried stool that can be painful to eliminate from your body.


Part of the colon’s job is to dehydrate food and turn it into stool. When your colon is inflamed, it’s less able to absorb the water content in undigested food. This results in diarrhea — watery, loose stool, and bowel urgency.

When you have diarrhea, you may also experience abdominal pain and a bloated, uncomfortable feeling.

Talk with a doctor about your UC symptoms. Several medications help treat bloating, as well as constipation, excess gas, and weight gain.

Treatments for UC include medications, such as corticosteroids, that relieve inflammation in the colon. Reducing inflammation will help the tiny ulcers in your colon heal.

Treating your ulcerative colitis as a whole may be enough to reduce bloating, gas, and other uncomfortable symptoms.

Your doctor may also recommend that you add an anti-gas medication containing simethicone to your treatment plan. There are several brands available without a prescription.

What you eat has a significant impact on UC bloating, weight gain, and constipation. Keeping a food diary may help you identify foods that trigger symptoms.

Follow a low FODMAP diet

Many people with UC find that following a low FODMAP diet is helpful for relieving bloating and other digestive symptoms.

FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are short-chain carbohydrates (sugars) that may be challenging to digest. Eating foods high in FODMAPs can cause bloating and abdominal discomfort in people with UC.

Eat smaller meals

Eating small amounts of food several times a day, rather than three large meals, may help reduce bloating.

Drink more water

Drinking water may also be beneficial. Water helps relieve constipation, which can reduce bloating. If you have diarrhea, drinking lots of water will also help you stay hydrated.

Move more

Exercise and physical movement may help as well. Walking after eating, rather than sitting or lying down, will support good digestion and help prevent bloating. It may also reduce stress, which can affect UC symptoms.

Is ulcerative colitis hereditary?

The exact cause of UC is unknown. However, there does seem to be a genetic link. You may be more likely to have UC if a close relative, such as a parent or sibling, also has it.

Learn more about the genetic factors behind UC here.

What other conditions cause bloating?

Bloating can be caused by conditions that co-occur with UC, such as small intestinal bacterial overgrowth (SIBO). SIBO affects the small intestine but causes the same symptoms as UC.

Your period can also be another cause of bloating.

Does stress cause UC flare-ups and bloating?

It may. Stress doesn’t cause UC, but it may increase how often you have flare-ups and the severity of your symptoms.

Managing your stress can be challenging, but it may help with your overall quality of life. To reduce stress, consider adding stress-relieving activities like exercise and meditation to your weekly routine. Therapy may also help.

Ulcerative colitis can cause bloating, along with other gastrointestinal symptoms like constipation. This is due to the inflammation and ulcers that UC causes.

If you have UC, changing your diet and taking medications may help relieve symptoms and reduce UC flare-ups.