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Testing for SIBO


The Hydrogen/Methane Breath Test with lactulose challenge is used to diagnose SIBO. This test can be performed in at a hospital or clinic lab, but take home collection kits have become available and more commonly used. The test is performed after the cessation of certain medications that interfere with your regular intestinal motility, digestion, and microflora balance. A 1-2 day preparation diet is also required. We will outline SIBO collection instructions below and have included some videos that should be watched before performing a SIBO test. 

How to Collect Breath Test Instructional Video

Breath Test Preparation Instructional Video

Before Testing

If you are not able to comply with these guidelines for testing, then you may not be a candidate for a breath test and your doctor can assist you in determining if another test without these preparation limits is more suitable. 

  • No antibiotics or antifungals 2 WEEKS (14 days) BEFORE TESTING. Finish taking any antibiotics or antifungals (except those who are re-testing following SIBO treatment).

  • WAIT TWO WEEKS (14 days) after surgery, colonoscopy, enemas, or colonics.

  • 4 DAYS BEFORE YOUR TEST avoid all laxatives. This includes (high dose) vitamin C and magnesium that is being taken specifically to induce a laxative effect.

  • No fermented foods 1 day before testing.

  • No smoking, including second-hand smoke, for at least 1 hour before or at any time during the breath test.

  • No sleeping or vigorous exercise for at least 1 hour before or at any time during the breath test.

Before you start the breath test, a 24-48 hour preparation is required consisting of a 1-2 day (12-36 hour) restricted diet and a 12 hour fasting period (stop eating in the early evening the day before testing and do not eat until after you test that following morning). 

If you are uncertain if something will affect the test, avoid the product/ food or consult your physician prior to starting the test.

Prep Diet

If you suffer from constipation, follow the SIBO preparation diet for 2 days (36 hours). If you suffer from diarrhea, follow the SIBO preparation diet for 1 day (12 hours).

The first 12 or 36 hours is the restricted diet.  Limit your foods to those below, and nothing else:

  • You may drink plain water, coffee, tea (no sugar/artificial sweeteners or cream added)

  • Baked or broiled chicken, fish or turkey. (Salt and pepper only)

  • Plain steamed white rice

  • Eggs

  • Clear chicken or beef broth (meat broth not bones with cartilage)

The goal of the SIBO preparation diet is to starve your bacteria for a day in order to produce the best test results. SIBO bacteria love plant products and sugars, so the only foods that you can have on the those listed above – if it is not on this list DO NOT eat it: 

Fasting Before the Test

Stop eating the evening before the morning of your test; similar to a fasting blood draw.  ​The last 12 hours DO NOT eat or drink anything, except water.




Frequently Asked SIBO Testing Questions​

What is lactulose?

Lactulose is a manmade sugar that humans cannot digest, but SIBO bacteria love; acting like fertilizer for SIBO bugs. Drinking lactulose will not cause the same “sugar-high” as sugars that humans can digest (like sucrose or fructose). Lactulose is also used as a laxative, so some people may experience effects of needing to use the restroom during the test. Sometimes people may feel an exasperation in symptoms caused by SIBO activity (like bloating, gas), but some people do not experience any at all.

Is Lactulose the same as Lactose?

No. Lactose is the sugar from milk, while lactulose is a completely different chemical makeup that is manmade. The lactulose that comes in the SIBO kits is a liquid solution. This solution, however, does contain 1.2 grams of lactose in it, so people who are severely lactose intolerant should ask their doctor if this test is right for them.


Which medications will affect the outcome of a hydrogen breath test?


  • Do not take these the day of the test

Laxatives (such as Metamucil, Dulcolax, Ex-Lax)

  • Stop taking 1-4 days before taking test


  • Stop taking 4 weeks before taking test (in some cases 2-weeks)


  • Stop taking 1-4 days before taking test

Can I use seasonings during the restricted diet?

The only seasonings allowed are Salt and Pepper; used in moderation.

Can I chew gum during the preparation period?

No, gum is not allowed during any part of the preparation period.



How do I ship back at-home collection breath test kits?
Mail back USPS (United States Postal Service). Kits mailed to patients will include shipping labels. The gas tubes are highly stable therefore regular shipping is recommended. Sample must be received within 7-days of collection​.

Is breath testing


​SIBO Preparation Diet Length

Constipation = 2 days

Diarrhea = 1 day 

Basic Breath Testing Guidelines

SIBO testing performed in the clinic.


Test in the clinic or take home collection materials. 

Reduced costs, discounted retesting and fast turn-around-time. 

The number of people with IBS with SIBO


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