Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
You drink a sugar solution, and breath samples are collected over 2 to 3 hours.
Why it's done
- Bloating, gas, or diarrhea after dairy
- Possible SIBO
Getting ready and what happens
- Follow a special low-fiber diet the day before and fast overnight.
- Avoid antibiotics for 4 weeks and laxatives for a week, if possible.
- Don't smoke or exercise before the test.
How the test is done
- You breathe into a bag before and every 15 to 30 minutes after drinking the solution.
What the results mean
Rise in hydrogen or methane
Suggests lactose intolerance or SIBO, depending on the sugar and timing.
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
Related conditions
Related medicines
Sources
Last updated 2026-11-13.