Need help and support in completing your hydrogen and methane breath test?

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If you have received a postal hydrogen and methane breath test or are attending an appointment at one of our clinics, you can find information below on the preparation that is required prior to doing your test and videos showing how to carry out the test.

For 4 weeks before your test

Do not take any antibiotics.

For 1 week before your test

Do not:

  • Take laxatives or stool softeners – Movicol, Dulcolax, Ex-Lax, Senna, Milk of Magnesia etc
  • Take stool bulking agents – Metamucil, Citrucel etc
  • Take motility agents – Prucalopride, linaclotide etc
  • Take probiotics – VSL#3, Actimel, Yakult etc.

You can:

  • Continue taking any other essential medicines

Additional information

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

You must follow the ‘white food diet’ which consists of the only the following foods and drinks:

  • 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.

For 12 hours before your test

You must stop eating and drinking and fast for 12 hours before your test

On the day of your test

You may:

  • Have small sips of water (maximum of 300 ml) until the start of your test
  • Take your essential medicines with a small amount of water but do not take anything that may affect your bowel (see previous list)
  • 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 your test

Additional information

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.

If you have any questions regarding your test and how to complete it:


SIBO hydrogen and methane breath test instructional video

Lactose/fructose hydrogen and methane breath test instructional video

An excellent service from beginning to end. I would recommend to anyone who was considering having testing done. Very friendly and knowledgeable

Manchester Patient