Skip to content

    Find a Vitamin or Supplement


    Other Names:

    B. subtilis, B. subtilis natto, Bacillus inaqosorum, Bacillus spizizenii, Bacillus stercoris, Bacillus subtilis subsp. inaqosorum, Bacillus subtilis subsp. spizizenii, Bacillus subtilis subsp. stercoris, Bacillus subtilis subsp. subtilis, Bacill...
    See All Names

    BACILLUS SUBTILIS Interactions
    BACILLUS SUBTILIS Overview Information

    Bacillus subtilis (B. subtilis) is a type of probiotic ("good" bacteria) found naturally in the human gut. It's also found in fermented foods.

    "Good" bacteria such as B. subtilis might help the body break down food, absorb nutrients, and fight off "bad" organisms that might cause diseases. These bacteria are sometimes added to fermented foods like yogurt and also found in dietary supplements.

    People use B. subtilis for diarrhea from antibiotics. It is also used for athletic performance, eczema, constipation, indigestion, gas, irritable bowel syndrome (IBS), and many other conditions, but there is no good scientific evidence to support most of these uses.

    Don't confuse B. subtilis with Bacillus coagulans, other probiotics, nattokinase, or with fermented food products such as fermented milk, kefir, or yogurt. These are not the same. Also note that three previously recognized Bacillus subtilis subspecies have recently been reclassified. Some products marketed as B. subtilis might actually contain these newly classified Bacillus species, including Bacillus inaqosorum, Bacillus spizizenii, and Bacillus stercoris.

    BACILLUS SUBTILIS Uses & Effectiveness What is this?

    Possibly Effective for:

    • Diarrhea in people taking antibiotics (antibiotic-associated diarrhea). Taking B. subtilis by mouth seems to help prevent diarrhea from antibiotics.
    There is interest in using B. subtilis for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

    BACILLUS SUBTILIS Side Effects & Safety

    When taken by mouth: Some B. subtilis strains are commonly consumed in foods. As medicine, B. subtilis is possibly safe for most people. B. subtilis strains BS50, B2335, CU1, MB40, MY02, and R0179 have been used safely in doses of 2-10 billion colony-forming units (CFUs) daily for 2-8 weeks. It seems to be well-tolerated.

    Special Precautions & Warnings:

    Pregnancy and breast-feeding: There isn't enough reliable information to know if B. subtilis is safe to use when pregnant or breast-feeding. Stay on the safe side and stick to food amounts.

    Children: There isn't enough reliable information to know if Bacillus subtilis is safe for children, including very small premature infants.

    Weakened immune system: Probiotics have caused blood infections in a small number of people with weakened immune systems. If you have a weakened immune system, talk with your healthcare provider before taking probiotics, including B. subtilis.

    BACILLUS SUBTILIS Interactions What is this?

    Moderate Interaction Be cautious with this combination

    • Antibiotic drugs interacts with BACILLUS SUBTILIS

      B. subtilis is a type of friendly bacteria. Antibiotics are used to reduce harmful bacteria in the body. Taking antibiotics along with B. subtilis can reduce the effects of B. subtilis. To avoid this interaction, take B. subtilis products at least 2 hours before or after antibiotics.


    In adults, B. subtilis has most often been taken by mouth alone or together with other probiotics in doses of 2-5 billion colony-forming units (CFUs) daily for up to 8 weeks. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.

    Be the first to share your experience with this treatment.

    Review this Treatment

    Learn about User Reviews and read IMPORTANT information about user generated content

    Conditions of Use and Important Information: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

    This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version. © Therapeutic Research Faculty 2009.

    Search for a Vitamin or Supplement

    Ex. Ginseng, Vitamin C, Depression

    Today on WebMD

    vitamin rich groceries
    Do you know your vitamin ABCs?
    St Johns wart
    Ease hot flashes and other symptoms.
    Are you getting enough?
    Take your medication
    Wonder pill or overkill?
    fruits and vegetables
    Woman sleeping
    Woman staring into space with coffee
    IMPORTANT: About This Section and Other User-Generated Content on WebMD

    The opinions expressed in WebMD User-generated content areas like communities, reviews, ratings, or blogs are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. User-generated content areas are not reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance, objectivity, or any other reason except for compliance with our Terms and Conditions. Some of these opinions may contain information about treatment or uses of drug products that have not been approved by the U.S. Food and Drug Administration. WebMD does not endorse any specific product, service, or treatment.

    Do not consider WebMD User-generated content as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of something you have read on WebMD. You should always speak with your doctor before you start, stop, or change any prescribed part of your care plan or treatment. WebMD understands that reading individual, real-life experiences can be a helpful resource but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified health care provider. If you think you may have a medical emergency, call your doctor or dial 911 immediately.