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8th September, 20219 min read

What causes bloating in your stomach?

Medical reviewer:Dr Ann Nainan
Author:Dr Adiele Hoffman
Last reviewed: 03/09/2021
Medically reviewed

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What does bloating mean?

Bloating is that too-full feeling after you’ve had a big meal, when your stomach feels stretched, swollen and tight. We’ve all had a bloated stomach at some point in our lives, but some of us get it more often than others do.

Bloating usually happens when your tummy (abdomen) is filled with gas or air. It may look bigger than it usually does, or it may look exactly the same but feel bigger. It can feel hard to the touch, and sometimes, it may be very sore.

If you’re bloated, you may also have other symptoms like tummy pain, farting (flatulence), burping (belching) and tummy rumbling or gurgling.

The most common causes of a bloated tummy include problems with your digestive system like trapped wind, food intolerances and irritable bowel syndrome (IBS). But sometimes, bloating may mean you have fibroids in your womb or a build-up of fluid in your tummy (ascites).

You can usually treat a bloated tummy at home with self-care, but if you’re feeling bloated all the time, you have severe bloating or very painful bloating, it’s time to see a doctor.

Why is my stomach bloated?

There are a number of different reasons why you might have a bloated tummy. Here are some of the most common causes.

Trapped wind

Trapped wind is a build-up of gas in your digestive system, which can often make you feel bloated. It’s normal to have gas in your gut, as it’s part of your digestion. Gas is made when your food gets broken down, or digested in your gut. This gas travels through your gut and can come out as burps or farts. If you have gas-related symptoms, it’s not because your body produces more gas than usual, it’s that you’re more sensitive to gas.

Gas usually builds up when you swallow air while eating or drinking, especially if you drink fizzy drinks, for example.

And if you get bloating after eating, certain foods may be to blame, as they create more gas. These include:

  • Brussels sprouts
  • broccoli
  • foods containing soluble fibre – like fruit, peas and beans
  • starchy food like potatoes

Other causes of trapped wind include food intolerances and medicines like certain laxatives including lactulose, and metformin (a diabetes medicine).

For some people, broccoli, peas and beans may cause trapped wind, which may lead to a bloated stomach

Food intolerances

Food intolerances happen when your body can’t digest certain foods properly, which often makes you feel bloated. This may be because you don’t have enough digestive enzymes, which help break food down, or you have a sensitivity to a chemical.

You may get these symptoms if you have a food intolerance:

These are some of the foods that are the most likely to cause an intolerance:

  • lactose – found in dairy products like milk
  • fructose – a sugar found in fruit
  • salicylates – compounds found in foods including fruit, vegetables, herbs, spices and artificial flavourings
  • gluten – a protein found in wheat, barley and rye

Being intolerant to gluten is different from coeliac disease, which is a more serious autoimmune reaction to gluten (where your body fights against its own tissues). It can also cause bloating and other severe symptoms, so see a doctor if you think you have symptoms of coeliac disease.


Constipation is when you have hard poo and don’t poo very often (less than 3 times a week).

It can make you feel bloated because the longer your poo sits in your bowel, the more time the bacteria that live in your gut have to break your poo down and release gas. It can also be harder for the gas to get past your poo, causing more bloating.

Causes of constipation include:


Indigestion (dyspepsia) is a common cause of upper abdominal bloating and discomfort, and isn’t usually serious. It usually happens when the lining of your stomach is irritated, often by acid or food.

It can also be a symptom of a condition like a peptic ulcer or gastro-oesophageal reflux disease (GORD).

Symptoms of indigestion include:

  • feeling full and bloated
  • feeling sick (nausea)
  • heartburn – a burning feeling in your chest or throat caused by acid reflux, which is when acid rises up from your tummy
  • vomiting food or tasting a bitter fluid in your mouth
  • burping and farting

The causes of indigestion include medications like antibiotics and non-steroidal anti-inflammatories (NSAIDs), your diet, smoking and obesity.


IBS is a collection of symptoms relating to your gut – and it may make your body produce more gas than normal. It often causes bloating and gas like burping or farting, especially after you’ve eaten.

IBS symptoms vary between people and may include:

  • tummy cramps – usually worse after you eat or poo
  • diarrhoea
  • constipation

The exact cause of IBS isn’t known, but it’s thought to be related to:

  • your gut being oversensitive
  • food going through your digestive system too quickly or too slowly
  • having a close family member with IBS
  • stress

Read more about which foods and drinks cause farting.

Diet changes like avoiding certain foods or eating more fibre can help treat a bloated stomach

Hormonal causes

People with a vagina often experience bloating at certain times in their lives due to hormonal changes. For example, having higher levels of oestrogen causes your body to hold on to too much water, which causes bloating. Examples include:

  • bloating from your period – this usually happens in the week or 2 before your period starts and can be a symptom of premenstrual syndrome (PMS)
  • bloating in early pregnancy – you’re also more likely to get constipation and indigestion when you’re pregnant
  • menopause bloating – this often happens during perimenopause, just before the menopause

Less common causes of a bloated stomach

Sometimes, you may get bloating from these less common causes:

What’s the best treatment for a bloated stomach?

Your treatment will depend on what’s causing your bloating. There are lots of things you can try at home to get rid of trapped wind including changing your diet to limit foods that cause bloating and exercising more regularly. Read more about how to get rid of trapped wind and natural ways to beat bloating.

IBS and constipation can also also be treated at home, as long as you or a doctor are sure there’s nothing else that could be causing your symptoms. For example, IBS usually gets better if you manage your stress levels and get more exercise. You can also keep a food and symptoms diary to try and work out what is triggering your IBS – and then exclude those foods or drinks. This is helpful with food intolerances too.

If you have indigestion, diet changes also work well, as well as stopping smoking, not eating too close to bedtime and losing weight. Read more about ways to get rid of indigestion.

But if you’re finding that even with these changes, your bloated stomach isn’t getting better, you may need treatment advice from a pharmacist or a doctor. This could include medications to reduce the acid in your stomach known as antacid medicines or laxatives to help with constipation.

For more serious causes like ascites or cancers, you’ll likely need treatment in hospital. This may involve surgery or medication like chemotherapy.

Read more about how to get rid of bloating.

Exercising more regularly can help get rid of bloating in your stomach

When to see a doctor about bloating

You can usually manage bloating with self-care. But you should see a doctor as soon as possible if you have bloating and:

  • it’s very bad
  • you’re losing weight without meaning to
  • it keeps coming back
  • It’s painful or happening overnight
  • you also have tummy or pelvic pain
  • blood in your poo
  • a high temperature (fever)
  • you’re vomiting
  • your skin or the whites of your eyes are yellow (jaundice)
  • diarrhoea, or a change in your poo habits that can’t be explained, like pooing more often than usual with very runny poo
  • you can feel a lump in your tummy
  • you’re over 50
  • you have trouble swallowing
  • you feel full quickly or don’t feel like eating
  • you need to pee more often or need to pee urgently
  • you’re having abnormal vaginal bleeding, or vaginal bleeding after you’ve been through the menopause

Call an ambulance or go to hospital if you feel bloated and:

  • you suddenly can’t pee or haven’t peed all day
  • you’re vomiting and it looks like blood, coffee grounds or it’s bright green, or you can’t keep any fluids down
  • have very bad tummy pain
  • you haven’t had a poo or farted all day
  • you have a lot of blood in your poo or your pee
  • your poo looks like tar (dark black)

Your health questions answered

  • What causes a swollen stomach and weight gain?

    If you have a swollen stomach and have put on weight, the 2 could be connected – or not. If you’ve been exercising less than normal or your diet has changed, this may have caused you to put on weight and become constipated, which may be making your stomach look swollen. Another cause could be pregnancy. But if your stomach is swollen, it could also be that your body’s holding on to too much water and you’ve got a build-up of fluid in your tummy, which can also make it look like you’ve gained weight. It can be a serious problem, so see a doctor if you’ve got a swollen stomach and have gained weight.

Key takeaways

  • bloating is a feeling of fullness, tightness or stretching of your stomach
  • you usually get a bloated stomach because your abdomen is filled with gas
  • there are lots of causes of a bloated stomach including trapped wind, indigestion, IBS, hormonal changes and more serious conditions like ascites
  • a bloated tummy can usually be treated at home and gets better quickly, but other more serious causes will need the advice of a doctor
  • see a doctor if your bloating is severe, it’s not getting better or you have other worrying symptoms
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