Doctor's Note

What dose should we take and under what circumstances? See the first video in this series, Preventing and Treating Diarrhea with Probiotics. Then I compared probiotics to prebiotics in Preventing the Common Cold with Probiotics?, and Friday I'll end on Gut Feelings: Probiotics and Mental Health.

I was surprised to find so few actual data on this topic, but that is par for the course for much advice about dietary supplements. See, for example, this series:

Vitamin D supplements should also probably be taken with meals for maximum efficacy (Take Vitamin D Supplements With Meals).

For more context, check out my associated blog posts:  Probiotics and DiarrheaProbiotics During Cold Season?How Should I Take Probiotics?, and How Probiotics Affect Mental Health

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

  • Brian Humphrey

    Thanks again Dr. Greger for this informative video!!

  • Catherine B

    How about hyperactive intestines. Would probiotics and prebiotics help in that situation?

    • Anthony Gonsalves

      Hyperactivity can be a result of the variety of cells trying to compensate for intestinal destruction while fighting pathogens in the gut, so I personally believe that pre and probiotics, but mainly food culture, can assist in helping the rebuilding, maintenance and battle-for-good in your gut. Also, just to note, prebiotics are usually fibers (or whatever non digestible substance) that promotes growth, well being and activity for gut flora.

  • Stephen Lucker Kelly

    So eating a pro-biotic vegan yogurt… would that be good?

    • Anthony Gonsalves

      Eating a probiotic yogurt may help, just be wary of the sugar content. Shoot for non-sweetened varieties and consume it with a whole fruit. Aside from probiotic yogurts though, consuming more fermented/cultured foods (and probiotic supplements if you desire, I don’t rely on them) will aid in the defense line and repair crew of your gut.

      • LynnCS

        Skip the dairy and go directly to whole fruits and vegis, grains, starches. The dairy causes mucus which adds to the gut trying to rid the body of them. The fiberous natural foods will heal the gut, sweep it clean, and give the little gut bacteria something to grow on.

        • Bruce

          I heard the man say FAT CONTENT. Seems odd that your interpretation did not include FAT.

  • Veganrunner

    Man we are getting so smart.

  • EdieP

    Re: probiotics for diarrhea

    Seven years ago, I had a serious case (all 10 biopsies came back positive) of microscopic colitis. I had been sick — and getting progressively worse — for several months, had become severely lactose intolerant, and had lost 15 pounds. Other options eliminated (liver nearly destroyed, with talk of transplant possibly necessary), my gastroenterologist said the only remaining option was corticosteroids. Having spent a lifetime keeping my weight under control, I refused, saying I’d rather die, and, frankly, expected to do just that.

    My husband put me on an “all white food diet” (nothing to stress the colon) that he found on the Internet and bought the most potent probiotics he could find. With his treatment, I was completely cured in about six weeks.

    I am a firm believer of probiotics… And VERY glad I refused the steroids.

  • PamyCST

    A question we have all pondered…. Thanks!

  • Kristin

    I have a question…are probiotics recommended as a daily supplement or just as a “treatment” for a period of time after taking antibiotics (or for some other digestive issue)? If the latter, for how long should they be taken?

    • EdieP

      From my experience, if you needed them once, better keep taking them. They’re expensive, so I’ve tried dropping them after all seems well, but every time I do, it isn’t long before problems begin to resurface.

    • Toxins

      You only need to take them a few times before the bacteria in you gut will self colonize. Adding more probiotics after this point is pointless. Typically diet determines which strain will proliferate.

      • John

        There are very few, if any, probiotic strains that actually colonize (they are foreign organisms to the body after all), most do not last. So yes, you need to take them on a regular basis.

        • Toxins

          Gut bacteria feed on soluble fiber and the colony grows. Plant food is known as a prebiotic for this reason. The gut is an ecosystem of its own, the flora is not threatened by the bodies immune system. There is no evidence to conclude that one must continue taking probiotics after the gut is colonized. Yes they are foreign, but they are not circulating throughout the blood stream.

          • name

            And is their ability to remain within the gut dependent upon the existence of an appendix? There are many variables here…

    • Nan

      Just went to a seminar where the Phd recommended 2 weeks on and 2 weeks off. If the bacteria get too used to being supplemented, they could get lazy and not reproduce. If you give them a little shock every 2 weeks, they remain strong. I am in the midst of trying it.

  • Sharon

    i particularly like when you make written comments on the audio as I often do not have time to listen to the complete audio version. I think I am a visual learner, rather than auditory. Mthx, love you info.

  • Autumn Sage

    Does cooking kill the probiotics in a food? Does Tempeh contain probiotics? Can Tempeh be eaten straight from the package without cooking?

    • John

      The answers are : yes, no and no. Tempeh does not contain any known probiotic. Unless specifically added no naturally fermented product can contain probiotics. These have to be added specifically. As tempeh is a fungus, it is wiser to fry or cook it before eating.

  • Darryl

    A slight tangent, but as living with pets has been associated with reduced infections and allergies in children (, I thought this recent paper examining the microbiota of families with dogs was worth sharing. Dogs are bringing a bit of nature back into our sanitary, but less biotically diverse households, and sharing it with us:

    Song, Se Jin, et al. “Cohabiting family members share microbiota with one another and with their dogs.” eLife 2 (2013).

    Dogs: the probiotic for your household.

    • Thea

      Darryl: The study you point out reminds me of a study that I saw summarized on TV not too long ago. They looked at the bacteria on the skins of a team of roller derby (? I think it was that – where they race around a tract in teams on roller skates) women. They looked before and after a game. After the game, the bacteria had changed significantly. The team members were sharing a lot more bacteria with each other. Or something like that.

      My (Great Dane) dog lies on my lap on the couch and licks my face in the morning to get me up. I imagine I’m just swimming in his microbiota (a new word for me). But as long as it’s mutual, I guess I have no reason to be grossed out.

      Thanks for bringing this up.

  • Thea

    I love it when a doctor tells me I have an excuse to eat, “a meal or beverage that contained some fat content.” ;-)

    Alas and alack, I don’t think I have a reason to take a probiotic supplement at this time. If I do find myself with the need in the future, I’ll be reviewing this video.

    Interestingly enough, it was my dog who recently needed a probiotic supplement after being on antibiotics. He ate a special probiotic powder made just for dogs for a couple of weeks in addition to his regular meals. I think it’s kind of funny that my dog got probiotics in light of Darryl’s comment about “Dogs: the probiotic for your household.” (nice comment Darryl!) Sort of a circular thing at my house.

    Just one more reason to love dogs!

    • DanielFaster

      Thea No need for supplements, just try some live wild cultured whole foods like cashew or other nondairy cheese, sauerkraut, kimchi, natto, miso, kombucha, mustard, nondairy yogurt, kefir water etc.

      • Thea

        I am a big fan of cashew cheese made of home-made rejuvalac. I’m just super-conscious of how calorie-dense it is. That’s a big concern for me. And of course, I couldn’t feed that to my dog…

        Also, I have no idea what/which probiotics are actually in the home-made rejuvalac – or if it makes a difference how old the stuff is. One theory I have is that the bad bacteria multiply and take over any good bacteria the longer the rejuvalac has been sitting in my fridge. My theory is that the anerobics are bad and anerobics can take over the longer the liquid is in an air tight container. I don’t have any evidence for that.

        Just some thoughts. I eat the cashew cheese for fun/taste, not for need. If I truly needed probiotics for a medical reason, I wouldn’t personally rely on any of those whole foods you listed. I would want to take something that is controlled with the correct/needed bacteria. If you have a link to a site showing specific analysis of the probiotics in the foods you mention, I would be interested in seeing that. I’m cuirous to know what was found and how much variation there is from product to product and batch to batch.

        Thanks for your thoughts.

  • Nettie

    Dr. Greger, I’m wondering if you could make a recommendation as to which brand or which bacteria I’m supposed to look for? (I recently had to take a round of antibiotics for a UTI.) There is a dizzying amount of products on the market, and I’m not sure what to look for. Do you have a favorite brand?

    • TCB Health

      Align is a good product and easy to find. It is packaged so that it does not need to be refrigerated, which makes it good for traveling or bringing to the office to take mid-day, if you prefer.

  • Wayne B

    Studies have shown the best time to take a probiotic is on an empty stomach before eating, preferably in the morning. But, if you’re not feeling better in a week, you may want to double the dose, so you’ll be taking it twice a day. This link ( has some good info about side effects.

    I work with EndoMune and I’d be happy to help answer any other questions you may have.

  • Derrek

    I have several problems like dandruff, a yeast body odor, and my flatulents really stink. Any ideas? I’m vegan and eat very little processed food. It might be because I have low levels of good bacteria in my gut.

  • Derrek

    What are the best sources of probiotics? I’m vegan and need to take probiotics I think.

  • acs84

    Thank you for these videos that answer questions I have a hard time finding answers to!!! If you get any info on brands of probiotics that would b nice!

  • Tim

    I’ve read about a probiotic called just thrive probiotic that claims 100% survivability because its in spore form. Not sure what that means or how true it is. Does anyone know anything about spore probiotics?

  • Alison

    How can you test a probiotic to see if it is still alive?

  • vamanos

    Why do I often get diarrhea after taking probiotics? Does that happen to anyone else?

  • Brian

    who conducted the study?