Is There Such a Thing as Too Many Probiotics? Here’s What You Need to Know

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    Probiotic doses are usually safe and overdose is unlikely. However, doses and types of probiotics might matter for your health.

    What are probiotics?

    Bacteria exist on almost all surfaces in the world. Some can be harmful, while others can be helpful. Probiotics are beneficial microorganisms (bacteria, yeasts, and others) that can promote the health of our bodies, including our digestive and immune systems.

    Types of common probiotics include Lactobacillus and Bifidobacterium species of bacteria, as well as Saccharomyces boulardii a probiotic yeast.

    Where are probiotics found?

    In the body, probiotics are present on the epithelial surfaces that line the internal and external organs. These areas include the gut, mouth, skin, and genital area. Each area where there is an ecosystem of microbes is called a microbiome, like the commonly known gut microbiome.

    Probiotics can also come from supplements as well as foods, such as yogurt, kefir, kombucha, raw sauerkraut, and kimchi.

    How much probiotics should you have each day?

    There is no established dose recommendation or upper limit for daily intake of probiotics.

    Probiotics are measured in colony forming units (CFU), which indicate the number of living cells of microbes. Many probiotic formulations have billions of CFUs per serving, some containing 1 to 10 billion CFUs per dose, while others contain up to 50 billion or more. Higher CFU counts do not necessarily improve the product’s health effects.

    Some practitioners may recommend certain doses and strains for different researched health benefits, but more studies are needed to further understand the clinical effects of different doses and strains.

    Potential side effects and risks of probiotics

    Overall, probiotics are considered a safe supplement. They are Generally Regarded As Safe (GRAS) by the FDA.

    If someone does experience side effects from probiotics, the most common symptoms are digestive-related symptoms, such as temporary gas, which can often resolve on its own.

    Certain probiotic strains as well as fermented foods containing probiotics may also increase levels of histamine in the body, which may cause symptoms in some people who may be sensitive. It can be helpful to work with a healthcare practitioner well versed in the use of probiotics for your health needs.

    Can probiotics be dangerous for certain people?

    Probiotics are known to support stronger intestinal gut lining and immunity and generally considered a safe supplement. Always talk to your doctor before starting any new supplements.

    Can you take too many probiotics?

    Depending on the person and their health needs, higher amounts of CFUs per serving can be considered too much. Pay attention to how your body feels when taking probiotics. Note how you feel when taking certain strains of probiotics, as well as certain doses. Always talk to your doctor or qualified healthcare professional about what you are taking.

    Can you overdose on probiotics?

    While it is possible to take too many probiotics for your specific tolerance level, “overdose” is not likely, in the sense of causing dangerous side effects. To date, according to this study, there have been no reports of harmful overdose events caused by probiotics.

    How to avoid overdosing with probiotics

    What is considered “too many” varies from person to person. Be sure to take probiotics only as recommended, whether by your qualified healthcare provider or per the supplement label.

    Consider starting with smaller doses at first in order to determine your level of tolerance. Sometimes the gut microbiome just needs time to adjust before it can tolerate higher doses of probiotics.

    Also consider starting just one probiotic supplement at a time in order to pinpoint which supplements you tolerate and which ones may be contributing to development of potential discomfort or symptoms, if any.

    Signs and symptoms of taking too many probiotics

    Minor gastrointestinal symptoms are common when first starting a probiotic. These may include abdominal cramping, nausea, soft stools, headaches, gas, and even taste disturbance.


    According to the World Health Organization (WHO), diarrhea is defined as the passage of three or more loose or liquid stools per day, or more frequent passage than is normal for the individual.

    Diarrhea or loose or soft stools can occur when starting probiotics. If these symptoms persist, this may be a sign of intolerance, suggesting a need to adjust the dose or type of probiotic altogether.

    For chronic diarrhea or bowel issues be sure to talk to your doctor as it may be a sign of more serious underlying health issues. Antibiotic related diarrhea is an area that probiotics may support.


    Bacteria in the gut use a process called fermentation to break down food to be metabolized. Fermentation often involves gas as a by-product, which may cause an increase in symptoms of gas, or flatulence, in your gut. Changes in the gut flora as a result of taking probiotics can result in gut bacteria, resulting in more gas than usual.


    Taking probiotics may result in bloating, which is a feeling of fullness in the abdomen. This symptom is often the result of gas in the intestines or changes in bowel movement frequency.


    Some probiotic-rich foods contain biogenic amines, which include histamine, tyramine, tryptamine, and phenylethylamine. In some people more sensitive to biogenic amines, these substances may cause symptoms including headaches and nausea.

    If probiotic-rich foods trigger symptoms, taking a probiotic supplement may be a better option. Some probiotic strains in supplements may also contribute to an increase in amines in the body while others do not. It is important to find which ones work best for you.

    Abdominal pain

    Probiotics may cause symptoms like gas, and changes in bowel movements may cause mild abdominal pain or cramping. These symptoms usually go away after your gut gets used to the probiotics.

    Ways to help reduce probiotic side effects

    Start with smaller doses and work your way up to the full dose. If you continue to experience symptoms for more than a week, drop down to a lower dose for a few days and see if you tolerate it.

    While symptoms often improve with time, taking your probiotic at night may help reduce the experience of symptoms during waking hours.

    Also look closely at the ingredients listed on the product label to avoid any allergens to which you are sensitive.

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    Dr. Carla Montrond Correia ND, CNS
    Medical Content Manager
    Dr. Montrond-Correia is a licensed naturopathic physician and a certified nutrition specialist (CNS). She holds degrees from University of Bridgeport, Georgetown University, and University of Saint Joseph, and supplemented her education with internships in the health and wellness space. She's focused on research, herbal medicine, nutrigenomics, and integrative and functional medicine. She makes time for exercise, artistic activities, and enjoying delicious food.
    Victoria Peck-Gray, RD
    Freelance Contributor
    Victoria is a registered dietitian and functional nutritionist who helps people with resistant weight loss and PCOS transform their metabolic health and lose weight through a functional nutrition and lifestyle approach that addresses root causes. She is owner of her private practice, Wonderfully Made Nutrition and also leads her group metabolic coaching program for women called The 4 Method.