Hydrogen Sulphide Breath Test

For symptoms such as diarrhoea, abdominal pain, and excessive eggy- smelling flatulence, this test measures this gas, to see if there is an overgrowth of this type of bacteria.

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What is a Hydrogen Sulphide Breath Test?

Hydrogen Sulphide gas can be produced by certain types of bacteria in your gut.


Our breath test allows us to measure this gas, to see if there is an overgrowth of this type of bacteria.

Excessive hydrogen sulphide can be associated with a variety of gut symptoms such as diarrhoea, abdominal pain, and excessive eggy-smelling flatulence.

This test can be performed on it's own, or in combination with a Hydrogen and Methane SIBO Breath Test.

How it works

You will provide an initial breath sample by blowing into a collection bag, which when analysed will give us your baseline reading.

Then, you will drink water containing lactulose solution. Further breath samples will be taken at 45, 90, and 180 minutes after you have finished this drink.

During the test, you will be asked to take note of any symptoms you experience and complete the symptom form, which will be interpreted alongside the breath test data.

Preparing for your test

Before you test, there are some things we ask you to do, to ensure safety and accurate results. This includes stopping certain medication and fasting for a short period.

Please read our patient information leaflet for full details.

For 1 week before your test

Do not take laxatives or stool softeners (Movicol, Dulcolax, Ex-lax, Senna, Milk or Magnesia etc.)

Do not take stool bulking agents (Metamucil, Citrucel etc).

Do not take motility agents

(Prucalopride, linaclotide etc.)

Do not take probiotics

(VSL#3, Actimel, Yakult etc.)

You can continue taking any other essential medicines.

*Additionally, there must be a period of one week between any tests which require cleansing of the bowel e.g. colonoscopy, barium enema, before having a breath test.

The day before your test

• Plain white bread

• Plain white rice

• White potatoes (no skin)

• Baked/grilled chicken, turkey, lean beef, lean pork, white fish (no oily fish)

• Maximum of 2 eggs

• Water (non-carbonated)

• Non-flavoured black coffee (no milk)

• Non-flavoured black tea (no milk and no herbal teas)• 1 tbsp butter/margarine/oil

• Salt to flavour food

Do not eat or drink anything else, eating prohibited foods could give false results for the test.

The day of your test

You can have small sips of water (maximum of 300 ml) until the start of your test.

You may take your essential medicines with a small amount of water but make sure you do not take anything that may affect your bowel (see previous list).

You may brush your teeth, but please try not to swallow any toothpaste.

Do not eat, drink, chew gum, smoke, eat breath mints and/or other sweets on the morning of or during of your test.

ⓘ If you are diabetic requiring insulin or diabetes medicine, please ask your doctor if you should change your morning dose. Oral hypoglycaemic medicines are usually not taken that morning until completion of the test and you start eating again.

Getting your test results

The results will be analysed by our clinical team to see if you there is an overgrowth of this type of bacteria.

Following your test, your data will be analysed and results written up into a report.

The report will be sent to both you and your referring consultant/doctor, who will explain the results to you in a follow-up consultation.

Paying for your test

Self-paying: If you are paying for this test yourself and not through insurance, the cost will be £200.


Combined Lactulose Hydrogen Sulphide/Hydrogen Methane Breath Test (in clinic) £400

This cost includes the breath test, analysis and report.

Insurance coverage

If you have private medical insurance, most companies can cover this for you.

Got a question or want to find out more about our tests?

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