Probiotics have been found to be safe at very high doses and as of yet, no upper limit to how many probiotics you can take has been found [1, 2].
Side effects are more common with probiotic foods than with probiotic supplements because probiotic foods tend to be high in histamine [3, 4, 5].
Those at risk of very rare side effects are adults and children with a severely weakened immune system or who are critically ill [6, 7, 8].
Even though high doses of probiotics are very unlikely to cause any kind of harm, it’s best to find the lowest dose that works for you (in order to avoid excess costs, inconveniences, or overreliance on supplements).
Have you been taking high doses of probiotics to support your gut health and are wondering if it’s possible to overdo it? Or have you started taking probiotics or eating probiotic foods and have symptoms such as cramping, bloating, and abdominal pain? Have you been wondering if taking too many probiotics is what’s causing your symptoms?
The good news is that it’s probably not the probiotics. Probiotics, even at high dosages, are generally very safe and do not cause adverse side effects.
Let’s take a closer look at the research to help answer the question “can you take too many probiotics” and look at a few other potential causes of your symptoms.
Can You Take Too Many Probiotics?
This is very unlikely, as even probiotics studied in large doses have shown to be safe with few, if any, side effects. In fact, the International Scientific Association for Probiotics and Prebiotics says that consumption of them should equal or exceed the daily dose tested in human studies . So, what does that mean for daily probiotics?
Clinical trials have tested probiotic dosages from 5,000 all the way up to 3.6 trillion colony forming units (CFUs) per day and found them to be safe even at the highest dosages [10, 11, 12]. Keep in mind that most probiotic supplements contain 1 billion to 10 billion CFUs, with a few more therapeutic formulas containing 50 billion or higher. To reach 3.6 trillion CFUs, you would have to take 360 capsules of a 10 billion-CFU probiotic in one day! This means you reallyshouldn’t have to worry about taking an extra probiotic or two here and there.
In addition to their excellent safety record, probiotics are key to wellness, supporting healthy immune function , improving gut function [14, 15], and may even improve mood [16, 17] and chronic pain [18, 19].
Of course, everybody is different and there may always be exceptions. Though rare, some people may experience side effects or negative reactions. This is very rare and most often occurs in children and adults who are critically ill, in post-operative care, have short gut syndrome, or who are severely immunocompromised [7, 8].
There are also theoretical risks of probiotics (possible risks that haven’t been studied or seen in studies so far), including systemic infections, toxic bacterial metabolites, or too much immune stimulation among sensitive people . However, given the substantial body of research finding probiotics in very high doses to be extremely safe, these are unlikely to be meaningful risks for the vast majority of people .
Possible Side Effects of Probiotics
Rarely, people do report side effects when starting probiotics. Most commonly these include: general mild gastrointestinal symptoms such as abdominal cramping, constipation, nausea, soft stools, flatulence, and taste disturbance , or symptoms of a “die-off” reaction, such as fatigue, irritability, headache, and flu-like symptoms .
We always want to listen to our bodies and because probiotics are changing our gut microbiome, it’s possible some people get a bit of stomach distress from adding in new microbes, even though they’re healthy bacteria. You may also have symptoms if undesirable microbes start to die off as your microbiome balances out (often described as a “die-off” reaction). However, again, this is very uncommon when taking probiotics.
While there’s no research that says starting with a lower dose of probiotics is safer, I have found that for some sensitive patients, starting with a lower dose and working up from there helps reduce these symptoms, allowing the microbiome to acclimate slowly.
Starting at a lower dose (for example, if your probiotics say to take one or two capsules a day, start with one) also helps you find your minimal effective dose for your digestive health.
You want to find your minimal effective dose, because this is the dose that is most helpful for you and balancing your gut bacteria. One way you can take “too many” probiotics is just by taking more than you need to balance your gut microbiota. If two capsules give good results, and taking three doesn’t increase your results, then taking just two is all you need for health benefits. This makes taking probiotics easier and will also help keep the cost down.
Can You Eat Too Many Probiotic Foods?
Can you take too many probiotic supplements? Generally, no. However, it’s definitely possible to experience symptoms from eating too many probiotic-rich foods.
Probiotic foods, such as kefir, kimchi, sauerkraut, and kombucha are where I see patients more often have negative gastrointestinal side effects. There are three common reasons for this: histamine intolerance, FODMAP sensitivity, or lactose intolerance. Let’s look at each of these in turn.
Histamine in Probiotic-Rich Foods
Fermented foods that contain natural probiotic bacteria also happen to be high in histamine [3, 4]. In fact, the fermentation process itself produces histamine .
For those who have histamine intolerance, which is when the enzymes the body uses to break down histamine in foods cannot do their job, histamine can build up and cause symptoms .
Histamine can cause stomach distress, as well as other common allergy symptoms such as skin (itching, eczema) or respiratory (runny nose, congestion) symptoms.
If you think you might be reacting to the histamines in fermented foods, remove them from your diet for a month and see if symptoms improve . In the meantime, get your probiotics from a quality supplement instead.
In fact, while we need more research on this, taking certain kinds of probiotics could theoretically help improve histamine intolerance . So it’s possible that taking probiotics may allow you to tolerate fermented foods again later.
High FODMAP Probiotic Foods
One other possibility is that the fermented food you are eating is high in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.) These are fermentable carbohydrates that ferment in the stomach, and in some people cause stomach distress such as bloating, cramping, and diarrhea. The most common high FODMAP probiotic foods are coconut yogurt, dairy yogurt, sauerkraut, and kombucha.
Just like with histamines, you can remove these for a month, and see if your symptoms improve on a low-FODMAP diet.
Lactose Intolerance and Probiotic Foods
Some people have lactose intolerance (a lack of the digestive enzyme, lactase, needed to break down lactose in dairy products) and dairy foods cause digestive system upset such as bloating, cramping, and diarrhea .
In these cases, it’s the dairy that is causing symptoms, such as in the case of yogurt and kefir, and not the probiotic strains in the fermented dairy. Additionally, many of these dairy foods such as yogurt are also high in FODMAPs, which could be causing gastric upset.
Remember to get a probiotic product that doesn’t contain dairy and remove probiotic-rich (and other) dairy foods if you have lactose intolerance.
Best Probiotic Strains for Wellness
Besides wondering if it’s possible to take too many probiotics, people often want to know what strains of probiotics they should be taking.
The good news here is that for most people, you don’t need to search for specific strains of probiotics. While any kind of probiotic is better than no probiotics, a mix of the three main categories of probiotics — Lactobacillus bacteria and Bifidobacterium, Saccharomyces boulardii (a type of beneficial fungus,) and soil-based probiotics — is what we’ve found to be the most effective for our patients.
Find Your Ideal Probiotic Dose (But Don’t Worry About Taking Too Many)
The research overwhelmingly supports that probiotics are safe, even at doses much higher than what any consumer product contains.
While you probably can’t take too many probiotics, you don’t need to take more than what helps improve your symptoms. Start off for a week at the lower recommended dose and if you don’t see symptom improvement, increase your dose from there until you find a dose that works for you.
I hope that this article helps you be more confident in your use of probiotics and troubleshoot any symptoms you may be having as you’ve started on your healing journey with probiotics.
If you would like to see how probiotics fit into a larger gut health program, you can read my book, Healthy Gut, Healthy You, where you’ll find all the protocols you need for wellness.
The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, including Triple Therapy Probiotic Powder Sticks, and we encourage you to research which products may be right for you.
Doron S, Snydman DR. Risk and safety of probiotics. Clin Infect Dis. 2015 May 15;60 Suppl 2:S129-34. DOI: 10.1093/cid/civ085. PMID: 25922398. PMCID: PMC4490230.
Comas-Basté O, Sánchez-Pérez S, Veciana-Nogués MT, Latorre-Moratalla M, Vidal-Carou MDC. Histamine intolerance: the current state of the art. Biomolecules. 2020 Aug 14;10(8). DOI: 10.3390/biom10081181. PMID: 32824107. PMCID: PMC7463562.
Parker EC, Gossard CM, Dolan KE, Finley HJ, Burns CM, Gasta MG, et al. Probiotics and Disease: A Comprehensive Summary-Part 2, Commercially Produced Cultured and Fermented Foods Commonly Available in the United States. Integr Med (Encinitas). 2016 Dec;15(6):22–30. PMID: 28223894. PMCID: PMC5312833.
Schnedl WJ, Enko D. Histamine intolerance originates in the gut. Nutrients. 2021 Apr 12;13(4). DOI: 10.3390/nu13041262. PMID: 33921522. PMCID: PMC8069563.
Didari T, Solki S, Mozaffari S, Nikfar S, Abdollahi M. A systematic review of the safety of probiotics. Expert Opin Drug Saf. 2014 Feb;13(2):227–39. DOI: 10.1517/14740338.2014.872627. PMID: 24405164.
Žuntar I, Petric Z, Bursać Kovačević D, Putnik P. Safety of probiotics: functional fruit beverages and nutraceuticals. Foods. 2020 Jul 17;9(7). DOI: 10.3390/foods9070947. PMID: 32708933. PMCID: PMC7404568.
Shahrokhi M, Nagalli S. Probiotics. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. PMID: 31985927.
Bibiloni R, Fedorak RN, Tannock GW, Madsen KL, Gionchetti P, Campieri M, et al. VSL#3 probiotic-mixture induces remission in patients with active ulcerative colitis. Am J Gastroenterol. 2005 Jul;100(7):1539–46. DOI: 10.1111/j.1572-0241.2005.41794.x. PMID: 15984978.
Gionchetti P, Rizzello F, Morselli C, Poggioli G, Tambasco R, Calabrese C, et al. High-dose probiotics for the treatment of active pouchitis. Dis Colon Rectum. 2007 Dec;50(12):2075–82; discussion 2082. DOI: 10.1007/s10350-007-9068-4. PMID: 17934776.
Larsen CN, Nielsen S, Kaestel P, Brockmann E, Bennedsen M, Christensen HR, et al. Dose-response study of probiotic bacteria Bifidobacterium animalis subsp lactis BB-12 and Lactobacillus paracasei subsp paracasei CRL-341 in healthy young adults. Eur J Clin Nutr. 2006 Nov;60(11):1284–93. DOI: 10.1038/sj.ejcn.1602450. PMID: 16721394.
Pagnini C, Saeed R, Bamias G, Arseneau KO, Pizarro TT, Cominelli F. Probiotics promote gut health through stimulation of epithelial innate immunity. Proc Natl Acad Sci USA. 2010 Jan 5;107(1):454–9. DOI: 10.1073/pnas.0910307107. PMID: 20018654. PMCID: PMC2806692.
Mujagic Z, de Vos P, Boekschoten MV, Govers C, Pieters H-JHM, de Wit NJW, et al. The effects of Lactobacillus plantarum on small intestinal barrier function and mucosal gene transcription; a randomized double-blind placebo controlled trial. Sci Rep. 2017 Jan 3;7:40128. DOI: 10.1038/srep40128. PMID: 28045137. PMCID: PMC5206730.
Sindhu KNC, Sowmyanarayanan TV, Paul A, Babji S, Ajjampur SSR, Priyadarshini S, et al. Immune response and intestinal permeability in children with acute gastroenteritis treated with Lactobacillus rhamnosus GG: a randomized, double-blind, placebo-controlled trial. Clin Infect Dis. 2014 Apr;58(8):1107–15. DOI: 10.1093/cid/ciu065. PMID: 24501384. PMCID: PMC3967829.
Ng QX, Peters C, Ho CYX, Lim DY, Yeo W-S. A meta-analysis of the use of probiotics to alleviate depressive symptoms. J Affect Disord. 2018 Mar 1;228:13–9. DOI: 10.1016/j.jad.2017.11.063. PMID: 29197739.
Huang R, Wang K, Hu J. Effect of Probiotics on Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. 2016 Aug 6;8(8). DOI: 10.3390/nu8080483. PMID: 27509521. PMCID: PMC4997396.
Chakiath RJ, Siddall PJ, Kellow JE, Hush JM, Jones MP, Marcuzzi A, et al. Descending pain modulation in irritable bowel syndrome (IBS): a systematic review and meta-analysis. Syst Rev. 2015 Dec 10;4:175. DOI: 10.1186/s13643-015-0162-8. PMID: 26652749. PMCID: PMC4674951.
Nilholm C, Roth B, Ohlsson B. A Dietary Intervention with Reduction of Starch and Sucrose Leads to Reduced Gastrointestinal and Extra-Intestinal Symptoms in IBS Patients. Nutrients. 2019 Jul 20;11(7). DOI: 10.3390/nu11071662. PMID: 31330810. PMCID: PMC6682926.
Shulpekova YO, Nechaev VM, Popova IR, Deeva TA, Kopylov AT, Malsagova KA, et al. Food intolerance: the role of histamine. Nutrients. 2021 Sep 15;13(9). DOI: 10.3390/nu13093207. PMID: 34579083. PMCID: PMC8469513.
Hrubisko M, Danis R, Huorka M, Wawruch M. Histamine Intolerance-The More We Know the Less We Know. A Review. Nutrients. 2021 Jun 29;13(7). DOI: 10.3390/nu13072228. PMID: 34209583. PMCID: PMC8308327.
Deng Y, Misselwitz B, Dai N, Fox M. Lactose intolerance in adults: biological mechanism and dietary management. Nutrients. 2015 Sep 18;7(9):8020–35. DOI: 10.3390/nu7095380. PMID: 26393648. PMCID: PMC4586575.
I care about answering your questions and sharing my knowledge with you. Leave a comment or connect with me on social media asking any health question you may have and I just might incorporate it into our next listener questions podcast episode just for you!
Transform your health
Every product is science-based, validated by real-world use, and personally vetted by Dr. Ruscio, DC.