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When you’re bloated, your stomach or abdomen can feel full and uncomfortable, or even painful.
This bloating happens when your gastrointestinal tract contains too much gas or air. Bloating can be mild, or more severe, and may present as:
– A visibly distended or swollen abdomen
– Feeling very full and uncomfortable
– Feeling of tightness in the abdomen
– Excess gas – belching and/or flatulence
– Rumbling or gurgling
There are several causes of bloating, so it’s important to diagnose the cause of your bloating and find out why it’s happening to you.

Prolonged periods of bloating could indicate an underlying health problem, if so you should see your GP.
Possible causes can include:
Irritable bowel syndrome (IBS diagnosis)
Ulcerative colitis, a form of inflammatory bowel disease (IBD), where the inner lining of the large bowel is inflamed and develops ulcers
Crohn’s disease, the other form of IBD, where some parts of your colon are inflamed
Too much bacteria in your small intestine (called small intestinal bacterial overgrowth, or SIBO)
Gastroesophageal reflux disease
Food intolerances, especially lactose or fructose intolerance
Producing too much gas (dysbiosis and fermentation)
Weight gain
Stress or anxiety
Delays in your food and drink moving on from your stomach (called gastroparesis)
Eating too quickly, so that you swallow too much air (called aerophagia)


Feeling bloated is no fun, but once you know what’s going on you can start to manage your symptoms and the underlying causes.
Testing options:
At the Functional Gut Clinic, we can run the following tests to diagnose the causes of bloating:
Gastric emptying test– which measures how quickly food leaves your stomach
Carbohydrate malabsorption breath test– which finds out if you have certain food intolerances (lactose or fructose)
Small intestinal bacterial overgrowth (SIBO) breath test– which finds out if you have an overgrowth of bacteria in your small intestine (called SIBO)
Oesophageal manometry– which measures the function of your oesophagus (food pipe)
24-hour pH impedance monitoring– which looks at whether you have any reflux
Colonic transit study-a non-invasive test which looks at how long it takes for faeces to pass through your bowl

No one ever talks about what a “normal poo” looks like. It’s not something that’s taught in schools. Many people don’t even know there are different kinds of faeces. However, its shape, consistency, colour, and frequency can provide clues about gut function.
Understanding what’s normal or not can help to catch a gut problem early on. If unusual changes persist, a comprehensive gut health check can help investigate what is happening beyond what you can see.
So what are the different types of poo? What does a healthy poo look like? And when should you book a gut health check? Find out below.
A healthy poo is generally brown, soft, formed, and easy to pass without pain or excessive straining. It is characterised as a Type 3 or 4 on the Bristol Stool Chart (see below).
Bowel frequency can vary more significantly between people. There’s no optimal amount, though most people pass a stool at least once per day.
Occasional changes after travelling, eating differently, becoming stressed, or experiencing a short illness are normal. Repeated or persistent changes are more significant than a single unusual stool.
The Bristol Stool Chart is a clinical tool that classifies stool by shape and consistency, from hard lumps to entirely liquid. Identifying the specific type can help understand bowel transit but cannot diagnose a condition by itself.
Type | What It Looks Like | What It May Indicate |
Type 1 | Separate, hard lumps | Constipation or slow movement through the bowel |
Type 2 | Sausage-shaped but lumpy | Mild constipation or slower bowel transit |
Type 3 | Sausage-shaped with cracks | Generally healthy and relatively easy to pass |
Type 4 | Smooth, soft, and sausage-shaped | Usually considered the ideal stool type |
Type 5 | Soft blobs with clear edges | Faster transit, although it may be normal for some people |
Type 6 | Mushy pieces with ragged edges | Mild diarrhoea or rapid movement through the bowel |
Type 7 | Entirely watery with no solid pieces | Diarrhoea, particularly if repeated |
It’s not just the consistency or shape of the stool that matters. Colour is often a key indicator of disease. Faeces are normally brown due to the presence of bile pigments. However, it can become green due to food colouring, leafy vegetables, or faster bowel transit.
Blood in the stool can either be fresh red, indicating lower bleeding, or black and tar-like, suggesting bleeding higher in the digestive tract. Iron tablets and some medicines can also darken the stool.
Very pale or clay-coloured stool can indicate reduced bile flow and should be assessed if it persists.
Changes in frequency are one of the clearest signs of bowel dysfunction. Look for changes in your usual routine rather than strictly measuring how often you go.
In particular, straining, urgency, or feeling unable to empty your bowel completely can help differentiate normal from abnormal frequency.
Lastly, a stool can be abnormal if it floats or comes with mucus. Floating stools commonly contain trapped gas and are not automatically unhealthy. However, if it’s persistently greasy, pale, or difficult to flush, it can suggest poor fat absorption.
Mucus isn’t always abnormal. But persistent mucus alongside pain or diarrhoea can indicate inflammatory bowel disease.
An occasional change in your stool is usually nothing to worry about. However, speak to your GP if you experience:
Blood in your stool or repeated rectal bleeding
Black, tar-like stools without an obvious explanation
Persistent pale stools, especially alongside yellowing of the skin or eyes
A lasting change in bowel habits or unexplained weight loss
Severe abdominal pain, symptoms that wake you at night, or diarrhoea with fever, dehydration, or significant weakness
These signs do not automatically mean something is wrong. However, it’s also best to speak to a clinician to assess the wider picture.
Stool appearance often changes with a gut condition. Different kinds of faeces can suggest a particular underlying problem, whether that’s inflammation, infection, malabsorption, or an intestinal barrier problem.
But these symptoms cannot determine exactly what’s going on.
A gut health test is often recommended to identify changes in microbial composition. Gut microbes influence everything from nutrient absorption to inflammation.
The Functional Gut Clinic is the UK’s first fully integrated full-spectrum microbiome clinic. We offer a range of tests to help you understand your symptoms and unlock the potential of your gut microbiome. We’ll provide you with a comprehensive, easy to understand, report to help you take the next steps to support your gut health.
Learn more about our testing options and take control of your health.
Check out the next article: Gut Microbiome and Cholesterol: How They Relate to Heart Health
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"After stopping my lansoprazole, every time I had a warm drink, I could feel it burn all the way down to my stomach. Thank you to Sam for making me feel at ease." - Manchester Patient

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Burning mid-chest, worse when bending or lying down

Difficulty going to the toilet, unusual stools, often with stomach ache or intestinal cramps, bloating, nausea or appetite loss

A burning pain in your chest, just behind your breastbone.
The pain is often worse after eating...

Bringing food or drink back up, difficulty swallowing, feeling that food or drink is stuck in your throat, horrible taste in your mouth

Dysphagia - difficulty swallowing, feeling that food or drink is stuck in your throat, horrible taste in your mouth

Loose or explosive stools, can’t get to a toilet in time

Cramps; sharp or dull pain, Bloating, Excessive belching, Nausea or vomiting

Stools leak unexpectedly, Can’t get to a toilet in time

Abdominal pain or cramping, bloating, changes in bowel habits and urgency, gas