The Functional Gut Clinic are now accepting self referrals (self pay patients only) for Hydrogen and Methane Breath Testing. Patients can refer themselves by contacting us via email or post with details of their clinical condition and the test they would like performed. The request will be triaged by our clinical staff and we will contact you if we need more information or if we think the test is inappropriate.

Self referrrals can speed up the diagnostic process and if you need a referral to discuss the results with a Doctor, we can also arrange this for you to make sure that in addition to a firm diagnosis you can then receive appropriate treatment from an expert Consultant or Dietitian

If you have any queries or questions then please email us at


How do I request a referral? 

You should explain to your GP that you are having digestive symptoms and would like to test the possibility that you may have small intestinal bacterial overgrowth or lactose / fructose intolerance. A downloadable information sheet is here (Patient History Form) which can be taken with you when seeing your GP.

Do I need to travel to London?

Patient's for hydrogen methane breath testing can either attend the Functional Gut Clinic, 22 Upper Wimpole Street, London, W1G 6NB or can perform the test at home via a postal breath test kit. Full instructions on how to perform the home test will be provided and telephone support given. A short video showing how we do breath tests can be seen below. 

How do I get my results? 

Results are emailed, faxed or posted to both the referring consultant/GP and the patient. 

Emma Visits The Function Gut Clinic for a Hydrogen Breath Test.

Watch this short video below that shows what patients can expect from a visit to the clinic.