Kombucha for Gut Health: What Human Studies Show and What to Check on the Label

Kombucha is tea fermented with sugar, yeast and bacteria. It’s marketed for digestion, gut bacteria and general wellness, often at several dollars a bottle. If you’re drinking it daily for your gut, here is what human studies show so far, and what to check before you stock the fridge.

The human evidence is new and limited

• Until recently, almost none. A 2019 systematic review searched the research through July 2018 and found just one study reporting kombucha results in people. Most claims came from lab and animal research.¹
• A 2025 trial randomly assigned 60 healthy adults to drink 250 mL a day of either a fiber-enriched kombucha or unfermented tea for six weeks. The kombucha group showed some changes in gut bacteria and a favorable shift in triglycerides.² That was a specially formulated drink, not a typical store bottle.
• A 2026 trial of 59 adults with excess weight added 200 mL a day of green tea kombucha to a reduced-calorie diet for 10 weeks. The kombucha group improved some cholesterol measures from where they started.³ Both groups were dieting, which makes the kombucha’s own effect harder to judge.

These are small, short studies. They don’t show that kombucha treats bloating, constipation or other digestive problems.

Check the alcohol

Fermentation can produce alcohol. Under federal rules, kombucha with 0.5% alcohol or more, at any point during production, at bottling or after bottling, is regulated as an alcoholic beverage.⁴ The rule covers the time after bottling because alcohol content can change in the bottle.

That matters if you avoid alcohol for health reasons, take medicines that interact with it, or are in recovery. Keep bottles refrigerated and check labels for alcohol content.

Check the sugar

Sugar feeds the fermentation, and some sweetness usually remains.⁴ Flavored kombucha may also include fruit juice. Compare the grams of sugar per bottle, not per serving, since one bottle can contain more than one serving.

Home-brewing

Home-brewed kombucha is harder to control for alcohol, acidity and contamination. If you brew your own, use clean equipment and follow a tested recipe, and stop drinking it if it smells or looks off.

If your gut needs attention

If you’re drinking kombucha to fix ongoing bloating, gas or changes in bowel habits, it’s worth finding the cause. Our guides to probiotics, gas and IBS cover common causes and when to see a clinician.

Try: “I drink kombucha every day hoping it will help my bloating, but nothing has changed. What should we test or try instead?”

Bloated by Dinner includes a Belly Clock log and a Test-It list with a visit script. Use them to track what you eat and drink, including kombucha, and how your gut responds. See the book.