Doctor's Note

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on tea. Also, there are 1,686 other subjects covered in the rest of my videos--please feel free to explore them as well!

You may also be interested in checking out my associated blog posts: Eating To Extend Our Lifespan,  Soymilk: shake it up!, and the first month.

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Robert Lajoie

    Hi Good Doctor…i read the link
    …Ok It seems some people’s body can’t handle the Therapeutic Kombucha…but the scientific studies I sent you above(link below) seem to indicate a larger truth that IT won’t harm you and be beneficial . i find it odd that your nicely presented report is biased and not balanced..from meeting you in Montreal I found you objective but what I get from your link and the non inclusion of the scientific studies as noble as the one you refer to
    is that you are into shock news rather than balancing the reporting of the studies you select…PLS correct your unbalanced report on Kombucha if you want to be helpfull rather than an alarmist…

    • Michael Greger M.D.

      Kombucha may indeed reduce the organ damage of irradiated rats, but not sure the relevance (unless you have a pet rat and your friendly neighborhood nuclear plant melts down?). As a physician I’m kind of a rather limited veterinarian–I only know about one species! But I’m not saying there aren’t benefits to kombucha consumption, I’m just saying that if you look at a systematic review of the clinical evidence the benefits may not outweigh the risks. In fact, why tolerate any significant risks in our diet? That’s why I have a low tolerance for recommending against the consumption of foods shown to have serious adverse effects.

      • Adrienne @ Whole New Mom

        I think it’s a little much to state that, based on 3 adverse reports (with no data about those cases at all) that there is too much risk in drinking kombucha. Maybe the issue lies in proper preparation. There are also rumors stating that lavender and tea tree oil lead to hormonal issues in boys, but that was based on 3 kids as well and wasn’t a study at all. Furthermore, I have heard that reports on PubMed can simply be paid for and put there. So we need to look at “evidence” there with an open, yet questioning, mind. I’d love to hear what you think about my points. Thank you.

      • Jen

        “I’m just saying that if you look at a systematic review of the clinical evidence the benefits may not outweigh the risks”

        Couldn’t you say this about nearly any food? Our ENTIRE diet is LOADED with significant risks. Remember when people were getting salmonella from spinach? 33 deaths from Listeria in Cantaloupes last year? Processed foods and soda which harden arteries and kill you slowly?

        ” In fact, why tolerate any significant risks in our diet? That’s why I have a low tolerance for recommending against the consumption of foods shown to have serious adverse effects.”

        Doc,I do NOT want to tolerate risks in my diet. However, as a health professional I would prefer if your public health education program was more focused on the mainstream, rather than the minority. We have so many other problems!

  • mica_m

    So the paper displayed here says ‘A Case Of Kombucha Tea Toxicity’. Was this literally one case? Or are there others? I can’t find much info aside from various references mentioning a single ‘rare case of myositis’ – this does not in anyway imply some kind of serious risk here. We do not know what else was going on with this ‘single case’ – did this person have other health issues? Was they on certain medication (known to cause lactic acidosis)? There can be a number of causes:

    An awful lot of people drink Kombucha (some on a daily basis). This sounds like a statistical anomaly.

    • Michael Greger M.D.

      This was just a case report (which means by definition just one patient is described), but as I noted above, a systematic review concluded the benefits may not outweigh the risks. This was just one of the latest cases. It’s certainly an extremely rare consequence of kombucha consumption, but just like with medications, even though side effects can be rare, one still has to balance the benefits and risks. So I’d much rather see people drink (green or white) tea straight, which has more proven benefits and fewer reported risks.

      • j j

        how do you feel about kefir? safe? there are several vegan options of kefir available.

      • Quite happy to be natural

        I find your position a bit funny given the way perscription drugs are perscribed at the massive number of lawsuits concerning them. Heck the bulk ogf my health issues were caused by the use of antibiotics. Fosomax was a difinant contributing factior in my moms death…didn’t know it until years later when the link was found between that drug and heart issues, which my mother never had until she started taking fosomax. My neighbors mom started haveing issues after taking fosomax, her dr. told her she was haveing panic attactks. Hah! nope it was the fosomax. The drug side effects are rediculous! Talk about the benefit not outwaying the risk. Far more risks to drugs than consuming kombucha. I love what Kombuchas has done for me! Crazy how easily dr. poo poo natural remedies and go nuts over the limited number of side effects but the industry won’t hardly admit to the side effects of drugs and especially the possibility that there are issues with immunizations…Hum interesting that the gov’t has the immunization injury fund…I wonder why that is!

        • sf_jeff

          Dr. Gregor does not seem the type of doctor to routinely over-medicate.

  • Robert Lajoie

    Thanks for comments Doctor..Granted …Foods have risks..and if you Got AIDS you need to be careful about what you drink…carefully made Kombucha is a health drink that is therapeutic and needs to be consumed with the understanding of possible side effects…The Kombucha I drink has been very helpful for me as my digestive system not so great…but caution in consumption quantity at start if Novice is needed especially if you have AIDS…as outlined in you toxicity study link above.

  • Ethan

    What about the beneficial pro-biotic organisms and EGCG in kombucha? If someone is able to balance their pH by consuming more alkaline foods, wouldn’t its consumption be justified?

  • Soniin

    I make and drink kombucha on a daily basis and give away the scobies to friends to start their own batches.  I think this article and doctor are ridiculous to suggest it is harmful.  As usual, anything rich in life and probiotics, are deemed harmful by the medical association, who would rather dispense drugs than actually give something helpful to a person.  BUT, Do no harm…. what a crock of ****

    • Toxins

      In the words of Jeff Novick

      “While Kombucha tea is widely promoted to have miraculous medicinal
      properties, there is no evidence that Kombucha tea is effective for any
      of the reasons it is promoted for.

      What is being sold as Kombucha today is a colony of numerous species
      of fungi and bacteria living together, which permeate the tea. The
      precise composition of any sample of Kombucha depends to a great extent
      on what was floating around in your kitchen when you grew it or the
      kitchen (room) where it was grown.

      The most common microorganisms found in Kombucha tea include species
      of Brettanomyces, Zygosaccharomyces, Saccharomyces, Candida, Torula,
      Acetobacter, and Pichia. However, some analyzed specimens have been
      found to contain completely different organisms, and there is no
      guarantee that they will be harmless.

      In addition, there are case reports, which suggest that Kombucha
      preparations can cause such problems as nausea, jaundice, shortness of
      breath, throat tightness, headache, dizziness, liver inflammation, and
      even unconsciousness.

      Mayser P, Fromme S, Leitzmann C, et al. The yeast spectrum of the ‘tea fungus Kombucha’. Mycoses. 1995;38:289-295.

      Food and Drug Administration. FDA cautions consumers on “Kombucha
      Mushroom Tea” {News release}. Washington, DC: US Department of Health
      and Human Services, Public Health Service, Food and Drug Administration,
      March 23, 1995

      CDC. Anticholinergic poisoning associated with an herbal tea — New York City, 1994. MMWR 1995;44:193-5.

      Srinivasan R, Smolinske S, Greenbaum D. Probable gastrointestinal
      toxicity of Kombucha tea: is this beverage healthy or harmful? J Gen
      Intern Med. 1997;12:643-644.

      Unexplained severe illness possibly associated with consumption of
      Kombucha tea—Iowa, 1995. From the Centers for Disease Control and
      Prevention. JAMA. 1996;275:96-98.

      Perron AD, Patterson JA, Yanofsky NN. Kombucha “mushroom” hepatotoxicity. Ann Emerg Med. 1995;26:660-66

      Sadjadi J. Cutaneous anthrax associated with the Kombucha “mushroom” in Iran [letter]. JAMA. 1998;280:1567-1568.

  • Mirna

    Doctor G, I love your site, but I read that Kombucha naturally produces B12 (among other things). Is this true, because I’m ready to send a sample of my own brew to get it tested. If true, this is fantastic news!

    Also, the animal tests don’t mean anything to me…I’m not a rat, pig, rabbit or dog and all those tests proved it to be unsafe. As an example; there are a number of toxic things my dog can’t eat, but onions and almonds are safe for humans. :)

    • Michael Greger M.D.

      I am not aware of any data suggesting kombucha can be relied on as a source of vitamin B12. Here’s what I would suggest: Safest Source of B12

  • dohduh

    What about the Cornell study? Sorry to use a commercial site, but this was the only version I could find that was more than an abstract. Granted it is from 2000, but the death of the woman often referenced was in 1995.

    • Toxins

      Because something has antimicrobial properties does not necessarily mean it is healthy for you, as we can see with alcohol. The study Dr. Greger presented is independent of this antimicrobial property so it shouldn’t matter as there is no dispute.

  • olothstar

    What about water kefir ? i have been making my own kefir with water kefir grains since i turned vegan to help get the probiotic i used to get in my yogurt. i don’t see any serious studies about it; have you come across any ?

    thanks for all your great work !

  • Occams_Razor

    This is fun learning at its best. I am still attempting to learn about vitamins, with a bit of fence-sitting about giving them up. Made easier, for the nonce, by me not having the money for them, after taking them for 35 years. I am totally NOT on the fence about eating a plant diet!

    This one may be more heartening. I learned to make some pretty good kombucha tea a few years ago. Mmm, cold, fizzy, tasty, they said it was good for me, what’s not to like? Especially when I am *not* one of those health food fanatics – there’s always one in every online board – who drink quarts of kombucha daily or, I sh*t you not, the broad on Marie Oser’s soy board who described her diet of soy this for breakfast, soy milk that, soy theotherthing for lunch, soy yogurt, soy this for dinner…. barf. Nut.

    But maybe I can relax and stop making it. Making it was waaay cheaper than the $4 (I sh*t you not) pints in the health food stores. [Spoken in a Dr. Greger voice] Not making it would be… even cheaper.

    Still makes one long for ca. 1967 Mad Magazine’s ideal business street. The health food store’s sign said: “We don’t overcharge for stuff just because it’s good for you!”

  • Matthew Cahn

    “Chunks of slimy fungus?” do your research, fungus is mycelium, kombucha has chunks of yeast.

    • Michael Greger M.D.

      I believe you are mistaken. Yeast are unicellular fungi. Kingdom fungi, phylum Ascomycota, class Saccharomycetes, order
      Saccharomycetales, then typically family Saccharomycetaceae.

      • Matthew Cahn

        Guess you’re right on that point. I still don’t think you’ve given a complete picture of the potential benefit’s / risks of Kombucha. There is a lot of other research out there yet you’ve only quoted ONE study. What about the high levels of antioxidants in Kombucha:
        Also the “Potential use of d-glucaric acid derivatives (found in Kombucha) in cancer prevention” :

        Also this paper quoted “Research conducted in Russia at the beginning of the century and testimony indicate that Kombucha can improve resistance against cancer, prevent cardiovascular diseases, promote digestive functions, stimulate the immune system, reduce inflammatory problems, and can have many other benefits.”

        I’m not saying that there aren’t health risks which is why proper standards are necessary to make sure Kombucha is prepared properly. Similar to Vodka, which can make you blind if it isn’t prepared properly.

  • Lee

    A short while ago I saw a video presentation from NutritionFacts site that included a chart for fruits, vegetables and grains for acid vs alkaline content. I have been unable to find this in my search of the site. Can you please help me to locate it? Thank you.

  • Dianne Barnard

    I was very sorry to have missed your lecture at St. Clair Hospital. I was waitlisted but after viewing this little snippet, I am glad that I didn’t go. I feel that you have a responsibility as a doctor to present information in a meaningful way. This is prejudicial and presented in a cutesy tongue in cheek manner that is disappointing. I think that if you find this information to be possibly life saving, then you should present it in a way that people can understand and not in an alarmist way. Sorry, not a fan of this video. I am disappointed! This is important information, not a joke.

    • HereHere

      In some way, I agree with you. This video is not balanced, although I’m not a kombucha drinker. Scrolling down the comments, there are many studies that people have put forward. That said, I attended Dr. Greger’s lecture two years ago, and it was quite good. It certainly helped educate an audience of people diagnosed with various forms of cancer, and those supporting them.

  • Jerusha

    Comparing Kombucha with Raw Homemade Vinegar:

    I was wondering if this could cause a similar problem with making your own vinegar. I know from other nutritionfacts videos that vinegar is good for you. If I made my own vinegar, which uses a similar process as kombucha making, and even has a “mother/scoby” like the one in kombucha….would the vinegar have the same health risks as kombucha? Or is there something different with vinegar that causes it to be safe, even when making it at home?

  • Cynthia

    Love your site, admire you greatly, but one day you will ferment and then drink your kombucha conclusion. We can all prepare a food badly and get sick from it, but considering the thousands of years and millions of folks who drink kombucha, its benefits do outweigh the very small risk so far reported. At a minimum you could have just asked people to be careful as to how it is prepared. As to the rest of your site, I raise my kombucha glass to you!

  • Rosemary Guy

    Excerpt from above link:
    While an under-fermented probiotic may harbor pathogens or fail to develop the beneficial nutrients, an over-fermented probiotic (higher in acetic acid) may overburden the stomach’s digestive juices. Here’s why. The acidic pH aids the stomach’s digestive juices and helps break down food and relieve stagnation. Acetic Acid from Kombucha and Lactic Acid from kefir are all weak acids. When ingested, they react with minerals such as Calcium, Sodium, Potassium and Magnesium in the body tissue and blood, to form alkalies. This reaction is termed Alkaline-forming foods. That is how an acetic kombucha tea actually helps alkalize the body. However you have to be very careful in not over doing this. An excess will rob your body of ionic minerals. A cup or two is fine, but large amounts of these acids are not a good idea. How much is too much? It is a relative term. For a normal healthy adult the amount is thought to be 4-8 fluid ounces daily. (see Drug interactions). This amount appears to be comparable to another popular folk remedy – Apple-Cider Vinegar. The most often repeated recommended dosage for ACV is one spoonful daily. The reason is that typically ACV is 5 % acetic acid – almost 5 times that of Kombucha Tea. There are other differences but our focus here is on the acetic acid. Kombucha tea is far less leeching (a common AMA complaint) and kombucha, because it is alkaline forming, will not create acidosis in a healthy individual. If it does it is far more indicative of a deeper more serious disorder.

  • Derrek

    What are some natural sources of good bacteria? I flatulate a lot and probiotics can be expensive.

    • counterbond

      hate to tell you brother but probiotic foods will just make you “flatuate” more…. saurkraut, pickles, kimchi, but kombucha doesnt really do that too bad

      • Derrek

        I think I have dysbiosis and a problem with low levels of good bacteria. That’s why I think it will help.

  • Cherry

    I also think it’s a bit much to label Kombucha as Harmful. Did the case study mention why THIS person had this reaction, and why not every single person who drinks Kombucha ends up in a coma?

  • Sally

    I do not hear evidence one way or the other in your “statement”

  • LDGourmet

    I wonder if there is more evidence you could share about ‘more harmful than helpful” for WHOM?

    I am finding kombucha helpful to my digestion. I drink water too, and hibiscus and green tea. But am I at risk for acidosis or toxicity? Isn’t kombucha just another fermented product we hear such good things about? I feel we need more info on this. Was that case review subject drinking homemade ‘booch? Gallon a day? Had pre-existing poor health?

    Is that case sufficient to stop drinking something I seem to find beneficial??