Abdominal bloating

Abdominal bloating is a feeling of pressure, fullness, or swelling in your abdomen, often called the belly. Your abdomen may also look larger than usual. Visible enlargement is sometimes called abdominal distension.

Bloating does not always mean that there is too much gas. It can also result from constipation, how food moves through the digestive system, or how the abdominal muscles respond to normal digestive contents.

An occasional bloated feeling after eating is common. Bloating that keeps returning, does not settle, or occurs with other symptoms may need medical assessment. Bloating is a symptom, so its importance depends on the pattern and any accompanying changes.

Bloating can affect your whole abdomen or one area. It may develop gradually during the day, particularly after meals, and improve overnight or after passing stool or gas.

You may notice:

• A tight, stretched, or overly full feeling
• Pressure or mild discomfort
• An abdomen that looks larger than usual
• More burping or passing gas
• Rumbling or movement in the belly
• Constipation, diarrhoea, or a change between the two
• Feeling full sooner than expected while eating

The amount of visible swelling does not always match how uncomfortable you feel. Some people experience strong pressure without obvious enlargement, while others have visible distension with little pain.

Bloating can have several overlapping causes.

Common possibilities include:

• Swallowed air: Eating quickly, chewing gum, drinking through a straw, smoking, or having fizzy drinks can increase swallowed air.
• Food fermentation: Gut bacteria break down carbohydrates that are not fully absorbed. This produces gas. Beans, onions, some fruits, wheat-based foods, and certain sweeteners can contribute.
• Constipation: Stool remaining in the bowel can cause fullness, discomfort, and difficulty passing gas.
• Food intolerance: Lactose in dairy products or other poorly absorbed carbohydrates may cause bloating, gas, and diarrhoea in some people.
• Irritable bowel syndrome: IBS can cause bloating with abdominal pain and changes in bowel habits. It does not damage the bowel, but symptoms may be persistent.
• Hormonal changes: Some people feel bloated before or during a menstrual period.

Less common causes include coeliac disease, in which gluten triggers damage to the small intestine, or delayed stomach emptying, known as gastroparesis. Changes in gut bacteria, some medicines, and previous abdominal surgery may also play a part.

Persistent swelling can occasionally result from fluid in the abdomen, an enlarged organ, or a growth. A bowel blockage is an urgent cause, particularly when swelling occurs with vomiting, severe pain, and an inability to pass stool or gas.

Seek emergency medical help if bloating or abdominal swelling occurs with:

• Sudden or severe abdominal pain
• Repeated vomiting and inability to pass stool or gas
• Vomit containing blood or material resembling coffee grounds
• Black or bloody stools
• Fainting, severe weakness, chest pain, or difficulty breathing

Contact a medical service the same day if the swelling is rapidly worsening, you cannot keep fluids down, or you have significant pain with fever. New swelling with yellow skin or eyes also needs prompt assessment.

Book a routine appointment if bloating:

• Happens frequently or continues for several weeks
• Is becoming more noticeable or uncomfortable
• Comes with unexplained weight loss or reduced appetite
• Occurs with ongoing diarrhoea, constipation, or abdominal pain
• Is associated with blood in the stool
• Begins after starting a medicine
• Occurs with pelvic pain, feeling full quickly, urinary changes, or unusual vaginal bleeding

These symptoms do not point to one specific diagnosis. They help determine whether testing is needed.

A healthcare professional will ask when the bloating started, whether it changes after eating or passing stool, and whether your abdomen becomes visibly larger. They may ask about your diet, bowel habits, menstrual pattern, medicines, previous surgery, weight changes, and family medical history.

An examination may include gently feeling and listening to your abdomen. Depending on your symptoms, a pelvic or rectal examination may be discussed.

Tests are not always necessary. When they are, they may include blood tests for anaemia, inflammation, liver problems, or coeliac disease. If coeliac disease is being considered, do not start a gluten-free diet before testing unless advised, because avoiding gluten can affect the results.

Stool tests, breath tests, ultrasound, or other scans may be appropriate for some patterns. An endoscopy, which uses a flexible camera to examine part of the digestive tract, is generally reserved for symptoms or test results that suggest it would be useful.

Treatment depends on the cause rather than bloating alone. If symptoms are mild and occasional, it may help to:

• Eat slowly and avoid gulping drinks
• Reduce fizzy drinks and chewing gum
• Take regular gentle exercise
• Eat smaller meals if large meals trigger symptoms
• Keep a short record of meals, bowel movements, and symptoms
• Treat constipation with advice from a pharmacist or healthcare professional

Fibre can help constipation, but increasing it quickly may worsen gas and bloating. Make changes gradually and drink enough fluid.

Avoid removing many foods at once. Restrictive diets can make it difficult to get enough nutrients and may hide useful patterns. If particular foods repeatedly cause symptoms, a dietitian can help assess whether a structured trial, such as reducing certain fermentable carbohydrates, is appropriate.

Some non-prescription products are marketed for gas or bloating, but their benefit depends on the cause. Ask a pharmacist whether a product is suitable for you, especially if you are pregnant, take other medicines, or have an ongoing health condition.

Bloating related to a meal may settle within several hours. Constipation-related bloating may improve after bowel movements become more regular. Symptoms linked to menstrual changes may follow a monthly pattern.

Some digestive conditions cause symptoms that come and go. Improvement may involve identifying triggers and treating bowel changes rather than removing all bloating immediately.

Arrange follow-up if a suggested change does not help, symptoms return frequently, or new symptoms appear. A change in the pattern can be more useful than the intensity of one episode.

Is bloating the same as having excess gas?

No. Gas can contribute, but constipation, food movement, gut sensitivity, and abdominal muscle responses can also create a bloated feeling.

Can stress cause bloating?

Stress can affect bowel movement and sensitivity through communication between the brain and digestive system. It may worsen symptoms, but new or persistent bloating should not automatically be attributed to stress.

Should I stop eating gluten?

Not without a clear reason. If coeliac disease is possible, testing is most accurate while you are still eating gluten. Discuss testing before making a long-term change.

When is daily bloating worth checking?

Book an appointment if it continues for several weeks, is worsening, or affects eating or daily activities. Seek earlier care if it occurs with weight loss, bleeding, persistent vomiting, or significant pain.