Is Kombucha Good for You? What Is in a Glass, What the Trials Found

Kombucha is sweetened tea fermented by a culture of yeasts and bacteria, and it is a food rather than a treatment: a glass holds some sugar, acids, a little caffeine and a little alcohol, plus live cultures if it has not been pasteurised, and the human trials of it are small; the trials of kombucha on its own found no difference between the people who drank it and the people who did not on their main outcomes, and the positive results came from a single-meal blood-sugar test and from drinks with inulin added.^{1, 4, 10, 13, 14, 16, 17, 19} The trials published since 2021 cover 11 to 90 people over a single meal to 12 weeks.^{10, 19} Most healthy adults can drink it; the NHS wording that applies in pregnancy, to babies and young children and to anyone with a weakened immune system is in the safety section below.^{28, 29, 31} Which drinks carry live cultures, and how kombucha compares with kefir and yoghurt drinks, is on what drinks have probiotics; the trial record for live cultures by use is on the Wellgard probiotics guide.

Evidence at a glance

• What is in it: caffeine 15 to 113 mg a litre and pH 3 to 3.2 in nine US products (a maker-funded study); a mean of 0.77% ABV across 684 kombuchas sold in one Canadian province; about 10 kcal a serving on 35 New Zealand labels.^{4, 6, 8}
• Live cultures: 8 of 12 US retail kombuchas carried live kombucha cultures, 3 of the other 4 only an added Bacillus strain, 1 no live cells.³
• Human trials: ten trial groups since 2021 with a PubMed record, 11 to 90 people, a single meal to 12 weeks, four of them maker-funded or maker-supplied; before 2021 a systematic review found one human study.^{10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21}
• Safety: case reports of liver injury and lactic acidosis, and lead poisoning from kombucha brewed or sold in ceramic vessels; no trial reported a serious adverse event.^{22, 23, 24, 25, 26, 27}

Sources checked on 2 November 2026.

What is kombucha?

Kombucha is black or green tea, sweetened with sugar and fermented for between about five days and three weeks by a mixed culture of yeasts and bacteria that floats on the tea as a rubbery mat of cellulose.^{1, 3, 4, 14, 16, 25} The yeasts turn the sugar into ethanol and carbon dioxide, lactic acid bacteria make lactic acid, and acetic acid bacteria oxidise the ethanol into acetic acid, which is why a finished kombucha is sour, lightly fizzy and lower in sugar than the tea it started as.³ Why a fermented drink is not a probiotic by default, and which drinks carry live cultures, is on what drinks have probiotics; in Great Britain no claim for kombucha or its cultures is authorised, so a lawful UK label says "live cultures" rather than "probiotic".^{2, 33} Whether a bottle has live cultures at all depends on what happened after fermentation: pasteurised and filtered kombuchas keep on an ambient shelf because the heat has killed the cultures, and the label states whether a drink is pasteurised where the name does not.^{3, 16} What a pasteurised kombucha is and is not, and why it is not a postbiotic, is on what are postbiotics.

What is in a glass of kombucha?

Residual sugar, organic acids, some of the tea's caffeine, a little alcohol and, if unpasteurised, live yeasts and bacteria, in amounts that vary more between bottles than most labels suggest.^{4, 6, 8, 9} Taking each in turn, with the figures that exist:

• Sugar. Whatever the culture has not yet used, plus any fruit or juice added after fermentation, so it depends on the recipe and how long the brew ran; the label states it. The labels of 35 New Zealand products averaged 44 kJ, about 10 kcal, a serving, with sugar the main thing that varied between them, and in Argentina 9 of 10 commercial kombuchas exceeded that country's sugar limit for the category.^{8, 9}
• Acids. Acetic acid is the predominant acid, with lactic and glucuronic acids in many brews; the nine US products all sat at pH 3 to 3.2.^{4, 9}
• Caffeine. From the tea. In the nine US products it ran from 15 to 113 mg a litre, so a 330 mL bottle carried roughly 5 to 37 mg; the study was funded by a kombucha maker, stated in the Sources.⁴
• Alcohol. A little. Under the Licensing Act 2003 a drink of 0.5% ABV or less at the point of sale does not count as alcohol, and a live bottle can rise above it if kept warm; the law, the measured surveys, the breathalyser question and the halal question are on is kombucha alcoholic.^{5, 7}
• Live cultures. Yeasts, acetic acid bacteria and lactic acid bacteria, if the drink was not pasteurised; the species and counts differ from brewer to brewer, and a UK label is not required to state them.^{3, 4, 32}

What does kombucha taste like?

Sour first, then a little sweet, with the tannin of the tea underneath and a light fizz; a bottle that has fermented longer or warmer tastes more of vinegar.^{3, 7, 9} When a trained panel tasted ten Argentine kombuchas, the ones rated most drinkable were sweeter and fruitier, and the least drinkable were astringent, bitter or carried off-flavours.⁹

What have the human trials of kombucha found?

Small changes in blood and gut markers that mostly did not differ between the kombucha group and the comparison group, in trials of 11 to 90 people lasting a single meal to 12 weeks.^{10, 11, 12, 13, 14, 16, 17, 18, 19, 20} Until 2021 there was almost nothing: a systematic review that searched to July 2018 found one human study of kombucha and no registered trial, and a 2003 review found no efficacy study at all.^{21, 22} The trial groups since then, each with design, size, drink, daily amount, duration, result and funding:

Read across, the table says three things. The one result that stands on its own is the single-meal one: a high-GI meal eaten with 330 mL of live kombucha produced a lower blood-sugar rise than the same meal with soda water, in 11 people, once.¹⁰ The bowel and triglyceride results came from drinks with inulin added, one of them pasteurised, so they test the fibre as much as the tea.^{13, 17} And the two largest trials of kombucha on its own found no between-group difference on their main outcomes, while the UK trial measured what the body does with the drink rather than health.^{14, 16, 19} None of the trials reported a serious adverse event, and none enrolled pregnant women, children or anyone with a weakened immune system.

Does kombucha burn belly fat?

No trial has found that it does. In the one trial that measured it, 59 adults with excess body weight ate 500 kcal a day below their needs for 10 weeks, half of them with 200 mL of green tea kombucha a day, and both groups lost weight, body mass index and body fat with no difference between them; the authors' words are that the kombucha "did not enhance weight loss".¹⁴ What did differ was a calculated index called the lipid accumulation product, built from waist circumference and triglycerides, which fell in the kombucha group.¹⁴ So the trial evidence on weight is one controlled trial, in which both groups lost the same amount on the same diet.

Is kombucha good for your gut?

The trials that measured the gut found fewer self-reported symptoms and small shifts in gut bacteria, and no between-group difference in the composition of the gut microbiota or in how leaky the gut lining was.^{12, 14, 18} In the 59-adult trial, the kombucha group reported fewer gut symptoms related to motility, and only the control group's faecal pH and permeability markers rose.¹⁵ In the 24-adult maker-funded trial, four weeks of about 473 mL a day produced what the authors call "modest impacts" on the gut microbiome, with a few short-chain-fatty-acid-producing bacteria more abundant at the end.¹² The two bowel-symptom results in the table came from drinks that were not plain kombucha, one with inulin and B vitamins added and one with blueberry syrup, and their authors call them a pilot and exploratory.^{13, 18} No gut claim for kombucha is authorised in Great Britain.³³ Seven things you can do to improve gut health has the diet changes that have been measured in trials, and foods high in Lactobacillus lists the fermented foods by species.

How much kombucha a day did the trials use?

Between 100 and 473 mL a day, most of them 200 to 330 mL, with 200 mL the commonest amount; no trial compared one amount with another, and none ran longer than 12 weeks.^{11, 12, 13, 14, 16, 17, 18, 19, 20} A 330 mL bottle is at the upper end of what has been tested, not beyond it. The questions people ask, can I drink kombucha every day and is one a day too much, have the same answer: the trials gave healthy adults a bottle or less every day for up to 12 weeks and reported no serious adverse event, though bloating, diarrhoea and heartburn were reported by some participants and one person withdrew for severe bloating, and the NHS says of probiotics that for people with a healthy immune system they "shouldn't cause any unpleasant side effects".^{12, 13, 14, 16, 19, 28} Three figures decide whether a daily bottle fits you rather than the trials: the caffeine, 5 to 37 mg a bottle on the US figures, less than a cup of tea; the sugar on the label, read against the rest of your day; and the acid, because kombucha sits at pH 3 to 3.2 and in a laboratory model, solutions mimicking acidic drinks at pH 2.5 to 3.5 softened tooth enamel, more so the more acid they carried, so it is a drink to have with a meal rather than to sip over an afternoon.^{4, 29, 36} If the caffeine keeps you awake, caffeine and sleep gives the half-life arithmetic.

Is there a downside to drinking kombucha, and who should not drink it?

For most healthy adults the downsides are the sugar, the acid and the small amounts of caffeine and alcohol described above; the people the NHS wording covers are pregnant women, babies and young children, and anyone with a weakened immune system.^{28, 29, 30, 31} In pregnancy, the NHS says that "if you're pregnant or planning to become pregnant you should not drink alcohol" and that "you should not have more than 200mg of caffeine a day"; no NHS page covers kombucha itself, and no trial enrolled pregnant women, so whether a drink at or below 0.5% ABV falls within that advice is a question for your midwife.^{29, 30} For children, the NHS says "tea and coffee are not suitable for babies or young children", and kombucha is a tea with a little alcohol in it.³¹ The NHS says that "if you have an existing health condition or a weakened immune system, you should talk to a doctor before taking any probiotic supplements"; a raw kombucha carries live cultures, so the same check applies.²⁸

Beyond those groups, the record is case reports, which show what can happen rather than how often. A 2003 systematic review found no efficacy study and several case reports of suspected liver damage, metabolic acidosis and cutaneous anthrax, with one death on record.²² Since then: a 54-year-old woman with severe lactic acidosis after drinking kombucha tea, who recovered fully once she stopped; a 42-year-old woman with no past medical history who developed severe acute liver injury with massive necrosis of the liver after three months of about 950 mL of kombucha a day alongside daily wine, an injury the authors attributed to the kombucha; and the 1995 Iowa report of two people with unexplained severe illness, one of whom died, after about two months of daily home-made kombucha, which the public health report titled "possibly associated" with the tea.^{23, 24, 27} Lead is the clearest hazard and it comes from the vessel, not the tea: in 2023 a Spanish family was poisoned by kombucha brewed and sold in ceramic containers, with lead at 0.95 to 47 mg per kilogram in the drink and the glaze found to leach 5.8 to 73 mg a litre, and in 1998 an Australian couple needed chelation after six months of kombucha brewed in a ceramic pot whose glaze pigment the authors believed the acids had eluted.^{25, 26} If you brew at home, that is the rule that matters: both lead reports involved glazed ceramic that the acids attacked, so brew and store in glass, and keep it in the fridge once it tastes as you want it, because a live brew goes on fermenting in the warm.^{7, 25, 26} If a drink makes you unwell, report it to your local authority's food safety team, which gov.uk finds by postcode; the Yellow Card scheme takes reports about medicines and medical devices, not food.^{34, 35}

What can a kombucha label say?

What is in it, not what it does: "live cultures" with the species and the count where the drink is unpasteurised, the sugar and the caffeine warning where the law requires one, and a vitamin wording only where the drink has been fortified to at least a source of that vitamin.^{32, 33} The Great Britain nutrition and health claims register has no entry for kombucha, fermented tea or any live culture apart from yoghurt's starter cultures, so a gut, detox or immune line on a kombucha is not an authorised claim.³³ The threshold for that caffeine warning and the tea exemption are on is kombucha alcoholic.³²

Kombucha is also sold dried, as a powder or sachet made from a fermented tea and mixed with water, sometimes with other ingredients and vitamins added. No published trial has tested a dried kombucha, so nothing in the table above applies to one in either direction. What such a label can state is what the drink will contain once made up: whether it carries live cultures and how many to the end of shelf life, its caffeine and sugar, and, where the drink is at least a "source of" vitamin B12 in the law's sense, the authorised wording that vitamin B12 "contributes to normal energy-yielding metabolism", "contributes to normal functioning of the nervous system" and "contributes to the reduction of tiredness and fatigue".^{32, 33} For any kombucha, bottled or dried, the label is the figure.

What we don't know

• Whether kombucha changes any health outcome in a healthy adult over months: the longest trial ran 12 weeks, the largest had 90 people, and the two largest found no between-group difference on their main outcomes (literature searched to 2 November 2026).^{14, 19}
• What a UK bottle contains: no published measurement of the alcohol, caffeine or sugar in a kombucha sold in the UK exists; the figures above are Canadian, American, New Zealand and Argentine.^{4, 6, 8, 9}
• How many of the live cultures in a raw kombucha survive the stomach, or what any particular species in it does: no trial has tested a named kombucha culture at a stated dose, which is what the 2014 definition would require before the word "probiotic" applied.^{2, 3}
• How often the harms in the case reports occur: nobody has counted, and none of the trials, which together analysed about 470 people for up to 12 weeks, reported a serious adverse event, though bloating, diarrhoea and heartburn were noted in some participants.^{12, 13, 16, 22, 23, 24}

Frequently asked questions

Is kombucha actually good for you?

It is a fermented tea that most healthy adults can enjoy, and the trials have not shown it to change a health outcome over weeks on its own: the two largest found no difference between groups on their main measures, and the single-meal test found a lower blood-sugar rise in 11 people.^{10, 14, 19}

Can I drink kombucha every day?

The trials gave healthy adults 200 to 330 mL every day for 6 to 12 weeks and reported no serious adverse event; read the sugar on the label, and have it with a meal because of the acid.^{14, 16, 19, 36}

Is one kombucha a day too much?

Not on the trial record: 330 mL a day for eight weeks was the UK trial's dose, and the only trial above that, about 473 mL a day for four weeks, saw fasting insulin rise within its kombucha group, a maker-funded finding in 16 people that no other trial has tested.^{12, 16}

What is kombucha good for?

As a food, for replacing a sweeter drink and for its live cultures where the label says it is unpasteurised; as evidence, for a lower blood-sugar rise when 330 mL was drunk with one high-GI meal, and for bowel symptoms in trials that added inulin to it.^{3, 10, 13, 17}

Who cannot drink kombucha?

The NHS wording covers pregnant women (no alcohol, no more than 200 mg of caffeine a day), babies and young children (tea is not suitable), and anyone with an existing health condition or a weakened immune system (the NHS says to talk to a doctor before taking any probiotic supplements; a raw kombucha carries live cultures, so the same check applies).^{28, 29, 30, 31} Anyone avoiding alcohol altogether should know that a live kombucha carries some.^{5, 6}

Sources

1. Marco ML, et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nature Reviews Gastroenterology & Hepatology, 2021. Expert consensus statement; several authors declare industry fees. PubMed 33398112.
2. Hill C, et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 2014. Expert consensus statement. PubMed 24912386.
3. O'Sullivan EN, et al. Viability and diversity of the microbial cultures available in retail kombucha beverages in the USA. Foods, 2024. Culture counts and sequencing on 12 retail products; no conflicts declared. PubMed 38890935.
4. Yang J, et al. Microbial and chemical profiles of commercial kombucha products. Nutrients, 2022. Composition analysis of nine US products: caffeine 15.1 to 112.6 micrograms per mL, pH 3 to 3.2, ethanol 0% to 1.29%; funded by an unrestricted educational grant from a kombucha maker, with one author on its scientific advisory board. PubMed 35277029.
5. Licensing Act 2003, section 191, meaning of "alcohol": excludes "alcohol which is of a strength not exceeding 0.5% at the time of the sale or supply in question". England and Wales. legislation.gov.uk.
6. Jang SS, et al. Ethanol concentration of kombucha teas in British Columbia, Canada. Journal of Food Protection, 2021. Composition survey, 684 samples by headspace gas chromatography; mean 0.77% ABV, median 0.62%, 31.5% above 1%; funding not stated in the record. PubMed 34143179.
7. Ivory R, et al. Determination of ethanol concentration in kombucha beverages: single-laboratory validation of an enzymatic method. Journal of AOAC International, 2021. Laboratory method validation on eight commercial kombuchas bought in Ireland; states that raw kombucha kept above 4 °C may continue to ferment; the authors are employed by the test kit's maker. PubMed 33291146.
8. Nordstrom K, et al. Comparing Alcolyzer and GC-FID for ethanol measurement in kombucha: insights from nutritional labeling and brewer practices in New Zealand. Journal of Food Science, 2026. Nine products tested and the labels of 35 read (43.6 kJ a serving on average); funding not stated in the record. PubMed 41536259.
9. Moccia T, et al. First characterization of kombucha beverages brewed in Argentina: flavors, off-flavors, and chemical profiles. International Journal of Food Science, 2024. Composition and trained-panel sensory survey of 10 products; acetic acid the predominant acid; 90% above the national sugar limit; no conflicts declared. PubMed 39963578.
10. Atkinson FS, et al. Glycemic index and insulin index after a standard carbohydrate meal consumed with live kombucha: a randomised, placebo-controlled, crossover trial. Frontiers in Nutrition, 2023. 11 healthy adults, single test meals with 330 mL of an unpasteurised kombucha; funded by an Australian Innovation Connections grant; one author consults to the kombucha's maker and two run a glycaemic index testing service. PubMed 36875857.
11. Mendelson C, et al. Kombucha tea as an anti-hyperglycemic agent in humans with diabetes: a randomized controlled pilot investigation. Frontiers in Nutrition, 2023. Randomised double-blind crossover pilot, 12 adults with type 2 diabetes, 240 mL a day for 4 weeks per arm with an 8-week washout; the study kombucha measured 1.5% ethanol; the drinks were donated by a kombucha maker, and two authors hold interests in a synbiotics company. PubMed 37588049.
12. Ecklu-Mensah G, et al. Modulating the human gut microbiome and health markers through kombucha consumption: a controlled clinical study. Scientific Reports, 2024. Randomised 2 to 1, 24 healthy adults (16 kombucha, 8 control), about 473 mL a day for 4 weeks within an 8-week study; funded by the kombucha's maker, with one author on its scientific advisory board. PubMed 39738315.
13. Isakov VA, et al. Evaluation of the efficacy of kombucha-based drink enriched with inulin and vitamins for the management of constipation-predominant irritable bowel syndrome in females: a randomized pilot study. Current Developments in Nutrition, 2023. Open-label randomised pilot, 40 women, 10 days, 220 mL a day of a pasteurised kombucha drink with 2.53 g of inulin and B vitamins against water; Russian Science Foundation; no conflicts declared. PubMed 38149073.
14. Fraiz GM, et al. Green tea kombucha impacts inflammation and salivary microbiota in individuals with excess body weight: a randomized controlled trial. Nutrients, 2024; and Bonifácio DB, et al. Effect of green tea kombucha within an energy-restricted diet on cardiometabolic risk markers in individuals with excess body weight: a randomized controlled trial. Journal of Food Science, 2026. One randomised controlled trial, 59 adults with excess body weight (30 kombucha, 29 control), 10 weeks, 200 mL a day on a diet 500 kcal a day below needs against the diet alone; Brazilian and Spanish public research funding; no conflicts declared. PubMed 39339787 and 41957662.
15. Bonifácio DB, et al. Effect of regular green tea (Camellia sinensis) kombucha consumption on oxidative stress and endothelial health in individuals with excess body weight: a randomized controlled trial. British Journal of Nutrition, 2025; and Fraiz GM, et al. The impact of green tea kombucha on the intestinal health, gut microbiota, and serum metabolome of individuals with excess body weight in a weight loss intervention: a randomized controlled trial. Foods, 2024. Two further reports of the same 59-adult trial: hydrogen peroxide lower with kombucha (p = 0.007), other oxidative-stress and endothelial markers unchanged; no between-group difference in gut microbiota or intestinal permeability; the Foods paper declares no conflicts and Brazilian and Spanish public funding, the British Journal of Nutrition record carries no funding statement. PubMed 40637142 and 39594049.
16. Lloyd AJ, et al. Daily consumption of kombucha influences the urinary and plasma metabolome in a healthy human cohort. Food Science & Nutrition, 2025. Randomised, double-blind, parallel trial, 56 healthy adults aged 18 to 71 (28 per group, 51 completing), 8 weeks, 330 mL a day of an unpasteurised canned kombucha against flavoured sparkling water; led by Aberystwyth University and funded by Innovate UK; one author owns the producer that supplied the kombucha and one is affiliated with an industry partner. PubMed 41089754.
17. Arce-López B, et al. Effect of fiber-modified kombucha tea on gut microbiota in healthy population: a randomized controlled trial. Current Research in Food Science, 2025. Randomised double-blind parallel trial, 60 adults (58 completing), 6 weeks, 250 mL a day of a commercial kombucha with inulin added after fermentation against unfermented tea; funded by the kombucha's maker, declared as a potential competing interest. PubMed 40689297.
18. Anselmini AM, et al. Physicochemical, bioactive, and clinical evaluation of blueberry-enriched kombucha as a functional beverage. Journal of Food Science, 2026. Controlled clinical trial, 39 adults, 28 days, 100 mL a day of a blueberry green tea kombucha (alcohol 0.20%), live against sterilised; Brazilian public research funding; no conflicts declared. PubMed 42757640.
19. Bonifácio DB, et al. Acute and chronic effects of green tea kombucha with and without grape skin extract on immune and oxidative stress markers in beginner runners: a randomized controlled trial. Journal of Food Science, 2026. Randomised three-arm trial, 90 healthy adults aged 18 to 45, 12 weeks, 200 mL a day; Brazilian public research funding; no conflicts declared. PubMed 42799570.
20. Costa MAC, et al. Regular consumption of black tea kombucha modulates the gut microbiota in individuals with and without obesity. Journal of Nutrition, 2025 (46 adults; no conflicts declared, funding not stated in the record); and de Campos Costa MA, et al. Regular black tea kombucha consumption is associated with improved insulin resistance and increased ADIPOQ expression in adults with obesity: a pre-post clinical trial. Food & Function, 2026 (36 adults; Brazilian and Italian public funders in the publisher record, no conflict statement in the record). Before-and-after studies without a control group, 8 weeks, 200 mL a day. PubMed 39732435 and 41870392.
21. Kapp JM, Sumner W. Kombucha: a systematic review of the empirical evidence of human health benefit. Annals of Epidemiology, 2019. Systematic review to July 2018: 310 articles screened, one human study found, no registered trials; funding not stated. PubMed 30527803.
22. Ernst E. Kombucha: a systematic review of the clinical evidence. Forschende Komplementärmedizin und Klassische Naturheilkunde, 2003. Systematic review of efficacy and safety: no efficacy study; case reports of suspected liver damage, metabolic acidosis and cutaneous anthrax; one fatality on record. PubMed 12808367.
23. Sannapaneni S, et al. Kombucha-induced massive hepatic necrosis: a case report and a review of literature. Gastro Hep Advances, 2023. Case report, one woman; discharged after six days, liver tests still improving at two months. PubMed 39132615.
24. Holbourn A, Hurdman J. Kombucha: is a cup of tea good for you? BMJ Case Reports, 2017. Case report, a 54-year-old woman with severe metabolic lactic acidosis; full recovery after stopping the tea; no competing interests. PubMed 29197835.
25. Munilla García Z, et al. Family outbreak of lead poisoning associated with kombucha made and sold in ceramic containers (in Spanish). Revista Española de Salud Pública, 2023. Outbreak investigation: lead 0.95 to 47 mg per kilogram in the kombucha, container migration 5.8 to 73 mg a litre, ceramic containers identified as the source; no conflicts declared. PubMed 37226984.
26. Phan TG, et al. Lead poisoning from drinking kombucha tea brewed in a ceramic pot. Medical Journal of Australia, 1998. Case report, a married couple, six months of drinking; chelation required; glaze pigment the suspected source. PubMed 9887919.
27. Centers for Disease Control and Prevention. Unexplained severe illness possibly associated with consumption of kombucha tea: Iowa, 1995. MMWR, 1995. Public health report of two cases, one fatal, after about two months of daily home-made kombucha; the role of the tea was not established. PubMed 7476846.
28. NHS. Probiotics. Page last reviewed 24 November 2022 (review overdue). nhs.uk/tests-and-treatments/probiotics.
29. NHS. Foods to avoid in pregnancy. Page last reviewed 15 June 2026. Caffeine: no more than 200 mg a day, 100 mg in a cup of instant coffee, 75 mg in a cup of tea; alcohol: "it's safest to avoid alcohol". nhs.uk/pregnancy/keeping-well/foods-to-avoid.
30. NHS. Drinking alcohol while pregnant. Page last reviewed 13 March 2023 (review overdue). nhs.uk/pregnancy/keeping-well/drinking-alcohol-while-pregnant.
31. NHS. Drinks and cups for babies and young children. Page last reviewed 5 October 2022 (review overdue). "Tea and coffee are not suitable for babies or young children." nhs.uk/baby/weaning-and-feeding/drinks-and-cups-for-babies-and-young-children.
32. Department for Environment, Food and Rural Affairs and Food Standards Agency. Food labelling: giving food information to consumers. Last updated 20 September 2022. The caffeine warning on drinks over 150 mg a litre, including concentrated or dried drinks as reconstituted, with the tea and coffee exemption. gov.uk.
33. Department of Health and Social Care. Great Britain nutrition and health claims (NHC) register. Last updated 19 May 2026. No entry for kombucha, fermented tea or any live culture other than live yoghurt cultures (lactose digestion); the vitamin B12 wordings may be used only for a food that is at least a source of vitamin B12. gov.uk.
34. GOV.UK. Find your local food safety team: contact your local council to report a problem with food standards or hygiene. gov.uk/find-your-local-food-safety-team; and Food Standards Agency. Report a food problem. Last updated 5 August 2026. gov.uk.
35. GOV.UK. Report a problem with a medicine or medical device (the Yellow Card Scheme). gov.uk/report-problem-medicine-medical-device.
36. Fernández CE, et al. Effect of pH and titratable acidity on enamel and dentine erosion. Clinical Oral Investigations, 2022. Laboratory and in-situ study of solutions simulating acidic drinks at pH 2.5 and 3.5; funded by a Brazilian public research foundation. PubMed 35588021.

General information, not medical advice. Kombucha is a food; if you are pregnant, have a condition that affects your immune system, or avoid alcohol for any reason, take the figures above to your midwife, GP or pharmacist. If a drink makes you unwell, report it to your local authority's food safety team.

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