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IBS, Bloating, Gas, Diarrhoea or Constipation.
Could it be SIBO?
Find out now. Get your SIBO test here. Results in 3 days - Quickest in the UK.

Buy your SIBO Breath Test here and join thousands of happy customers. 

This safe and easy to do at home Smart SIBO test kit includes everything you need to be able to investigate whether SIBO is the cause of your current digestive and health problems.

Your test kit will come with full instructions and a link to a video about collecting your breath samples but do let us know if you have any questions when it arrives as we are happy to help.

Results will be returned to you with a full interpretation within 3-4 working day of the lab receiving your samples.

Get your results within 3 business days, meticulously analysed by our accredited lab for swift access to vital information.

Results with insights from our Certified Functional Medicine team, boasting over 21 years of SIBO expertise and thousands of test reports reviewed.

10 breath samples collected over 3 hours meaning more accurate results than the usual 7 samples taken over 2.5 hours.

Help the climate and your wallet. Our UK lab keeps costs low. Your samples never travel internationally to Europe or the USA, reducing carbon emissions.

Returning your samples to the lab is easy.

Free UK 24 hour Royal Mail Tracked return postage is included with your test kit

All About Our SIBO Breath Test

There are two types of SIBO small intestinal bacterial overgrowth breath tests available in the UK.

Standard SIBO Breath Test UK

We tend to favour the Hydrogen and Methane breath test as do most SIBO world experts such as Alison Siebecker and Dr Mark Pimenthal. The test includes drinking a small amount of a sugary tasting drink that contains a nonabsorbable sugar which is often confused for lactose the type of sugar you find in dairy produce (so our test is dairy free). Because the sugary drink isn’t absorbed it passes through the whole of the small intestines enabling it to pick up SIBO in the early and later parts of the small intestines.

Glucose test

The glucose breath test is slightly more accurate but because glucose is absorbed higher up in the early part of the small intestines it can miss SIBO if the bacterial overgrowth is further along/down the small intestines. We can provide tis test if you are interested please email [email protected]

Wouldn’t it be good to take control and find out if SIBO is the cause of your digestive issues.

Our SIBO test is a simple to do at-home test – You collect 10 breath samples over 3 hours and send them back to the lab for processing and analysis (postage is included with your kit). We receive the results and our certified team of Functional Medicine practitioners comment on your results. If anything isn’t clear we can set up a free 10-minute call to answer any questions you may have about your results. 

What don’t we do?

We don’t include a plan to address your SIBO along with your results – Why not? 

Because everyone is different and because SIBO is chronic in two-thirds of people, meaning it comes back unless you to dig into the possible reasons why you have SIBO.  So alongside treating the SIBO you need to address the root cause (or causes) so an off the shelf programme wouldn’t be the right fit for everyone.

There are also a few different treatment options available for addressing SIBO; the choice of program depends on whether you are hydrogen or methane positive, whether your symptoms and results look like a hydrogen sulfide positive and we also need to think about SIFO – small intestine fungal overgrowth.

A comprehensive program should also incorporate any other digestive imbalance which also need addressing as they may be causing or contributing to your SIBO. So we simply don’t think an off the shelf plan is the right option for you.

We do however work closely with a group of  Functional Medicine practitioners and experienced nutritional therapists along with a private GP. 

You will receive details of our practitioners with your results should you want to look into a bespoke personalised plan where your individual SIBO and digestive health picture is carefully investigated, tracked and supported.

Check out to read more about this.

What is SIBO?

SIBO – Small Intestine Bacterial Overgrowth quite simply means too much bacteria in the small intestines.

The only way to currently diagnose SIBO is by taking a SIBO hydrogen and methane or a glucose breath test.

Standard SIBO Breath Test

Glucose SIBO Breath Test

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    Standard SIBO Breath Test

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    Glucose SIBO Breath Test

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Did you know?


Cases of IBS that are actually Small Intestinal Bacterial Overgrowth (SIBO)


People with Small Intestine Bacterial Overgrowth (SIBO that have leaky gut​)


People with fibromyalgia that have Small Intestine Bacterial Overgrowth ( SIBO)

Signs and symptoms of SIBO

Small Intestinal Bacterial Overgrowth (SIBO) can affect people in many different ways. SIBO has been shown to exist in up to 84% of IBS patients and is therefore theorized to be the underlying cause of IBS.

Unsurprisingly digestive issues are the most common problems caused by SIBO; From bloating to constipation and / or diarrhea, indigestion or reflux. SIBO can also play a part in Chronic Fatigue (CFS), rosacea, restless legs, cystitis, prostate issues and many other health issues.

Symptoms of Small Bacterial Overgrowth

         Most common SIBO symptoms

  • Diarrhoea – usually associated with hydrogen dominant SIBO
  • Constipation – usually associated with methane dominant SIBO
  • Sulpherous smelling gas – commonly associated with hydrogen sulphide SIBO
  • Alternating constipation and diarrhoea
  • Gas
  • Flatulence
  • Belching
  • Bloating
  • Abdominal pain and cramps
  • Leaky gut  – Intestinal permeability

   Other related digestive SIBO symptoms

  • Malabsorption which can lead to Steatorrhea (Fatty Stool) or anaemia
  • Gall stones
  • Chronic pancreatitis
  • Milk (Lactose) intolerance
  • Fructose intolerance
  • Sucrose intolerance
  • Iron and B12 deficiency
  • Fatigue
  • Nausea
  • Acid Reflux
  • Gerd (Gastro oesophageal reflux disease)

      Less well known SIBO Symptoms

  • Acne rosacea
  • Skin rashes
  • Restless legs
  • Joint pain
  • Weight loss or gain
  • Food sensitivities
  • Incontinence
  • Headache
  • Interestitial cystitis
  • Rheumatoid arthritis
  • Chronic fatigue sydrome
  • Fibromyalgia
  • Brain fog
  • Ehlers Danlos syndrome
  • POTS
  • MCAS  – Mast cell activations syndrome

What causes SIBO

Research shows the main cause of SIBO is related to an issue with the movement of food through the gut when things move too slowly.  Think of a stagnant pond where algae grow in large unwanted amounts. The opposite is a fresh and clean free flowing river which helps to keep algae levels optimum. The bacteria in the gut are the same – if movement in the gut slows down, bacteria levels can build up to unwanted levels. 

The two main causes of slowed movement in the gut are;

  1. Food poisoning.  This affects the cleansing sweeping motion controlled by the  ‘Migrating Motor Complex’ (MMC).  This should switch on in between meals and should move undigested food and excess bacteria towards the large intestines.

  2. Structural changes which affect the motility of the gut can also cause SIBO. Some diseases, medical conditions and procedures can cause these changes. For example; endometriosis, scarring after operations, inflammatory bowel disease, and diverticulosis are all known to impact on or cause Small Intestinal Bacterial Overgrowth.

Contributory and risk factors that can affect SIBO

  • Low stomach acid – hypochlorhydria
  • Drug-induced hypoacidity (Low stomach acid) – This is commonly seen on those that take PPI’s Proton pump inhibitors PPI’s
  • Inflammatory bowel disease
  • Chronic alcohol use
  • Celiac disease
  • Chronic pancreatic insufficiency
  • Lactose intolerance – lactose is the type of natural sugar that you find in dairy products.
  • Damaged ileocecal valve
  • Immunodeficiency (especially of secretory immunoglobulin A)

How to treat SIBO - Small Intestinal Bacterial Overgrowth

World leaders in the battle against  Small Bacterial Overgrowth (SIBO) have been treating and researching SIBO for many years now and have found there are 3 main ways to address SIBO:

1. Antibiotics

The antibiotic Rifaxamin is considered the number 1 antibiotic of choice for hydrogen or Methane dominant SIBO and is often combined with neomycin when methane is present.

Rifaxamin isn’t licensed for use against SIBO in the UK however some people do manage to get a prescription from either their GP or gastrointestinal consultant. The IBS and SIBO clinic practitioners work closely with a private GP who is happy to prescribe Rifaxamin when suitable.

2. Antimicrobials

A  range of different natural plant based antimicrobials have been found to be as effective against SIBO as the antibiotics and these can also impact on SIFO (small intestine fungal overgrowth).

As the choice of antimicrobial is very dependant on the type of SIBO you have; hydrogen, methane or hydrogen sulphide, we recommend working with a knowledgable SIBO practitioner to ensure your programme is effective.

3. Elemental Diet

The elemental diet involves consuming a predigested drink that provides all of your daily nutrient needs but doesn’t feed the bacteria.

Studies show the elemental diet  helps to eradicate SIBO in 85% of people.

Many people shy away from this as they worry about weight loss and energy but if it is done correctly, with a practitioner if possible, this shouldn’t be an issue and shoudn’t be ruled out as it can be a very successful SIBO treatment.


There are also a number of different diets that can be used to help manage the symptoms of Small Intestinal Bacterial Overgrowth 

Diet alone will not eradicate bacteria in the small intestine.  Dietary changes can, however, support an antimicrobial programme and can help to make you more comfortable by relieving some symptoms.

The most common diets that are followed are the SIBO specific diet, The  FODMAP diet, SCD, Bi-Phasic diet and the Cedar’s Sinai Diet. 

Different people may find one of the diets is more suitable and effective than another one. This is thought to be due to the type of bacteria causing the overgrowth.


If you need help with a SIBO treatment plan we are happy to refer you to

The dedicated team at IBSandSIBOclinics have over 25  years of experience dealing with SIBO, IBS (Irritable bowel syndrome),  IBD (Inflammatory bowel disease) and other complicated digestive issues.  The practitioners attend all of the yearly world SIBO symposiums and keep up to date with the latest research. The founder Emma Wells is a Certified Functional Medicine practitioner and registered nutritional therapist with over 25 years of experience. Emma lectured on digestion and digestive testing for over 10 years. In the past Emma also had regular one one-on-one mentoring sessions with Dr. Alison Siebecker ND  – A top world-class SIBO practitioner and educator. also work with and refer people to a knowledgeable and experienced private doctor should you be one of their patients and need a private prescription for antibiotic treatment.

IBS and SIBO clinics are also happy to offer free 10 minute discovery calls to see how they can help you – please do visit their here website here to book yourself in for a free call.

Buy a SIBO test

There are two types of SIBO  – Small Intestinal Bacterial Overgrowth breath tests available.

The Standard SIBO Breath Test and the Glucose SIBO Breath Test.

We tend to favour Standard test as do most SIBO world experts.  We favour this test rather than the glucose tests as the solution you drink to test SIBO travels through the whole of the digestive tract and can catch SIBO in the later parts of the small intestine. 

The Glucose breath test is slightly more accurate but glucose is absorbed higher up in the early part of the small intestines and therefore can miss SIBO if the overgrowth is further along down the small intestines.

Standard SIBO Breath Test

Glucose SIBO Breath Test

  • Photo of a Glucose SIBO breath test

    Standard SIBO Breath Test

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  • Photo of a Lactulose SIBO Breath Test

    Glucose SIBO Breath Test

    Add to basket
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Did you know?

SIBO test UK
Our SIBO small intestine bacteria overgrowth test is available to purchase in the UK.

SIBO test Europe
We offer our SIBO, small intestine bacterial overgrowth test throughout Europe, All you need to do is check the appropriate box re shipping at checkout.  

SIBO test, rest of the world
We are happy to ship the SIBO small intestine bacteria overgrowth test kits all over the world. If your country isn’t covered when you get to the checkout please do get in touch with [email protected] and we will be happy to help.  Posting the kit out to some locations will include an extra postage fee.

How long do the results for the Smart SIBO (Small Intestine Bacteria overgrowth) test take?
The turnaround for the test is 3 – 4 working days. We do however aim to get results out sooner than this where ever possible.

How long can I take to do the Smart SIBO test? 
You need to complete the test in 6 months from the date of you order.

How long does it take to actually do the Smart SIBO  Small Bacterial Overgrowth  test?
The Smart SIBO test takes 3 hours to complete but you will need to follow a prep diet for 1 day before or, if constipated 2 days before the test.

I am doing both tests – Can I do the Standard SIBO Breath test and the Glucose breath test at the same time?
To ensure accuracy of the test results the tests need to be done on separate days. Please follow the prep diet and fast as instructed and complete test no 1. Please then continue with the prep diet and fast over night and collect the breath samples for test 2.

Is breath testing the best way to measure small intestinal bacteria overgrowth?
A recent research paper called “Hydrogen and Methane based breath testing in gastrointestinal disorders; The North American Consensus”  was published. This was made up of a group of scientist who looked at evidence about breath testing and concluded that breath testing was the best way to test for SIBO. The paper is freely available on the internet and can be found here.  

Will you explain what my results mean?
Yes,  We send an email with your results and we explain what your results mean – Whether they are hydrogen or methane positive or negative or if your results are looking like a possible hydrogen sulphide type of SIBO Small Bacterial Overgrowth.  We include a supporting document which explains how the test is interpreted which you can share with your health care provider if you wish.

What shall I do if my results are positive can you help?
Should your results be positive we would be very happy to refer you to where their highly trained and experienced practitioners are able to help you.  They offer Zoom appointments as well as in person appointments meaning they can see people all over the world.

If my results are positive is the programme to get rid of SIBO Small Bacterial Overgrowth included in the cost of the test?
Unfortunately not. The cost of the Smart SIBO test covers the cost of the test only. You would need to contact your doctor or health practitioner for treatment or we are happy to refer you to who will be happy to help you.

SIBO is too much bacteria in the small intestine, LIFO means too much bacteria in the large intestine and SIFO means small intestinal fungal overgrowth.  

Will the SIBO breath test be able to tell if I have SIFO (Small Intestine fungal overgrowth)?
Unfortunately not. You can do a simple urine test or a stool test that tests for the presence of fungal overgrowth but these tests cannot determine where in the digestive tract the overgrowth may be. If you are concerned about this or if you are interested in a test for fungal overgrowth then please do get in touch as we would be happy to discuss this with you. [email protected]

Can my child do the Smart SIBO Breath test?
As long as your child is over 50 Lbs and is able to blow into a tube then yes. If your child weighs less than 50Lbs then please get in touch as we will need to adjust how much of the solution they need to drink before the test.

What is the small intestine or small bowel?
Making up part of the digestive tract which is like a long tube –  the small intestine, also referred to as the small bowel sits in between the stomach and the large intestine. It is in the small intestine where most nutrients are absorbed and if normal levels of bacteria in the small intestine are present they help to keep the gut healthy.  The job of the large intestine is to mostly absorb water and form the stool. 

Should there be equal amounts of bacteria in the small intestine and the large intestine?
No, in a normal well functioning and healthy digestive tract you should have 100 thousand bacteria in the small intestine, also known as the small bowel, per 8th of a teaspoon where as you should have 10 to 100 billion bacteria per 8th of a teaspoon in the large intestine. 

Who are Smart Nutrition?
Smart Nutrition Ltd are the company that are providing you with your Smart Small Intestinal Bacterial Overgrowth SIBO Breath test. Smart SIBO test will show up on your order confirmation emails but Smart Nutrition Ltd will show up on your paypal receipt. Smart Nutrition Ltd was founded many years ago to offer a trustworthy health testing service to people with a range of health concerns. Smart Nutrition Ltd and Smart SIBO test use only fully accredited laboratories to assure you can trust your results.

Who is Emma Wells?
Emma Wells IFMCP, Dip ION, NTC, CNHC, mBANT is a fully qualified Nutritional therapist and certified functional medicine practitioner with over 26 years experience. Emma has lectured widely in many subjects including digestion and digestive testing and she keeps up to date by researching Nutrition and SIBO related news as well as attending twice yearly SIBO conferences. Emma Wells works as a consultant to Smart Nutritionof the 

I have a lactose intolerance and want to do the Smart SIBO test. Will this be a problem?
No this won’t be a problem. Both of our tests are dairy free. The hydrogen and methane test is easily confused with a lactose but contains a mixture of galactose and fructose to make up the test solution.

Do I need to follow any special dietary requirements for the test?
Yes, You will need to follow a special low fermentation diet for 1 day before the test or if constipated for 2 days. The Instructions include full details about the diet including meal ideas.

I am on a FODMAP diet and want to do the test – will it affect my results?
Being on the FODMAP diet will not affect your results unless you have been on the diet for more than 10 months.

I have just finished a course of antibiotics – Can I still do the Smart SIBO test?
You need a break of two weeks after antibiotics before you can do the Smart SIBO test.

I have just finished a course of natural plant based antimicrobials – Can I still do the Smart SIBO test?
You need a break of two weeks after a course of natural antimicrobials before you can do the Smart SIBO test.

I take probiotics – Can I still do the Smart SIBO test?
You need a break of two weeks after stopping probiotics before you can do the Smart SIBO test.

Can I take Laxatives the night before the Smart SIBO test?
Unfortunately not – laxatives would interfere with the test results. If your laxatives are prescribed please discuss with your doctor whether stopping them for 1 day is OK for you. You can take laxatives if needed on the day of the test  – after you have finished taking your breath samples.

Do I need to stop any supplements before doing the Smart SIBO test?
You need to stop probiotics for 2 weeks before the test. Digestive aids such as digestive enzymes and betaine HCL – stomach acid, should be stopped the day before the test.

Do I need to stop taking any medication before I do the Smart SIBO test?
Please do not stop any medication without the consent of your Doctor. In the past it was believed PPI’s needed to be stopped before testing, this is no longer the case. You can take the test whilst using PPI’s but on the day of the test please take your PPI after you have completed the test if authorised by your GP. Laxatives should not be taken the day before the test. Do not stop taking any medication without the approval of your doctor.

Can I drink water the night before the test when fasting?
Yes, drinking water is allowed whilst fasting.

I have just had a colonoscopy – Can I still do the Smart SIBO test?
You must wait at least 1 month after a colonoscopy before doing the Smart SIBO test.

I have just had some Barium studies – Can I still do the Smart SIBO test?
You must wait at least 1 month after a colonoscopy before doing the Smart SIBO test.

Preparation for the test
You will be sent full instructions with your Smart SIBO test kit. To do the test you will need to follow a prep diet for 1 day, or if constipated 2 days before the Smart SIBO test and then you will need to fast overnight before doing the test. Water is allowed whilst fasting. Your instructions include details about which foods you can eat and provide a meal plan as well.

On the day of the test
In the morning you will take a control breath sample and then drink the solution provided with the test kit. You then collect a breath sample every 20 minutes for the next 3 hours. After the last sample has been collected you can then eat and drink as normal.

Should I remove the grey rubber around the needle of the breath collecting kit?
No, Please don’t remove it. It helps to produce a good seal around the vial.

There is a hole in the blue breath collection bag. Should I tape it up?
The hole is there on purpose. Please don’t tape it up. It helps to get the correct breath sample.

Have you any tips re taking the breath sample?
Please have a look at the video that explains how to take the sample but feedback I have been given is that stand in front of a mirror may help you to see what you are doing.

Should I be able to see my breath in the test tube?
You generally won’t be able to see your breath go into the test tube but you might see some condensation. 

Returning your samples
Samples need to arrive back at the lab within 7 days of completing the samples.

The vials can be posted by airmail should you be outside the UK.

Getting your results

Results are returned in 3-4 working days.
Once processed (using the certified Quintron equipment) your results will be plotted on a graph. A rise in either hydrogen, methane or both at inappropriate points on the graph will demonstrate fermentation and the presence of bacterial overgrowth – SIBO.

We send out your results and let you know if your results are positive for hydrogen or methane SIBO. We also send a test interpretation guide which you can share with your GP or health care provider.

We are also happy to refer you to the IBSandSIBOclinics should you want help treating your SIBO or other digestive problems.


What our customers are saying about our breath testing and us

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Please do not return samples to the laboratories that may arrive after Wednesday 27th March and up to and including Monday 2nd April.

The laboratories are closed from the 28th March – 2nd April for the Easter Holiday.

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