Probiotics

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. Probiotics is used for Antibiotic-associated diarrhea, Clostridium difficile infection and Constipation.

Also called: Enzymedica (United States)

Pronunciation: pronunciation varies by local usage.

Generic name
probiotics
Drug class
Live microorganisms (bacteria and yeasts) used as dietary supplements, food ingredients, or, in some cases, drugs depending on intended use
Form
Not established by the sources used for this page. Probiotics can be found in yogurt and other fermented foods, dietary supplements, and beauty products.
Route
Taken by mouth (consumed) or applied to the body, depending on the product; dietary supplements can come as pills, capsules, powders, drinks, and energy bars
Legal status
In the United States, many probiotics are sold as dietary supplements, which do not require FDA approval before they are marketed; a probiotic marketed as a drug for treatment of a disease or disorder must be proven safe and effective through clinical trials and be approved by the FDA before it can be sold. Depending on a product's intended use, the FDA might regulate it as a dietary supplement, a food ingredient, or a drug.

Availability and supply rules vary by country

Trade names by country: United States

Australia: · Full directory

What probiotics is and how it works

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. They can be found in yogurt and other fermented foods, dietary supplements, and beauty products. Although people often think of bacteria and other microorganisms as harmful "germs," many are actually helpful; some bacteria help digest food, destroy disease-causing cells, or produce vitamins. Many of the microorganisms in probiotic products are the same as or similar to microorganisms that naturally live in our bodies. (1) (3)

A great deal of research has been done on probiotics, but much remains to be learned about whether they're helpful and safe for various health conditions. Probiotics have shown promise for a variety of health purposes, but in most instances we still don't know which probiotics are helpful and which are not, how much of the probiotic people would have to take, or who would be most likely to benefit. Dietary supplements do not have to go through the testing that drugs do. Cases of severe or fatal infections have been reported in premature infants who were given probiotics, and the FDA has warned health care providers about this risk. The risk of harmful effects from probiotics is greater in people who are seriously ill or have compromised immune systems.

Mechanism of action: how probiotics works

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. Probiotics may have a variety of effects in the body, and different probiotics may act in different ways. Probiotics might: help your body maintain a healthy community of microorganisms or help your body's community of microorganisms return to a healthy condition after being disturbed; produce substances that have desirable effects; and influence your body's immune response. (1) (3)

What is Probiotics used for?

Antibiotic-associated diarrhea

A 2017 review of 17 studies (3,631 total participants) in people who were not hospitalized indicated that giving probiotics to patients along with antibiotics was associated with a decrease of about half in the likelihood of antibiotic-associated diarrhea; however, this conclusion was considered tentative because the quality of the studies was only moderate. A 2016 review of 30 studies (7,260 participants), 5 of which focused on people age 65 or older, found probiotics may be helpful for antibiotic-associated diarrhea in young and middle-aged people, but a benefit has not been demonstrated in elderly people; it is uncertain whether probiotics actually don't work in elderly people or whether no effect was seen because there were only a few studies of people in this age group. A review of 23 studies (3,938 participants) of probiotics to prevent antibiotic-associated diarrhea in children provided moderate quality evidence that probiotics had a protective effect. (1)

Clostridium difficile infection

The bacterium Clostridium difficile can infect the colon of patients who have received antibiotics, causing diarrhea that can range from mild to severe; it is difficult to treat, sometimes comes back after treatment, is more common in people who take antibiotics long-term and in elderly people, and can spread in hospitals and nursing homes. A 2017 analysis of 31 studies (8,672 total patients) concluded that it is moderately certain that probiotics can reduce the risk of C. difficile diarrhea in adults and children who are receiving antibiotics. Most of these studies involved hospital patients. The analysis also concluded that the use of probiotics along with antibiotics appears to be safe, except for patients who are very weak or have poorly functioning immune systems. The types of probiotics that would be most useful in reducing the risk of C. difficile diarrhea, the length of time for which they should be taken, and the most appropriate doses are uncertain. (1)

Constipation

A 2014 review of 14 studies (1,182 participants) of probiotics for constipation in adults showed some evidence of benefit, especially for Bifidobacterium lactis. A 2017 evaluation of 9 studies (778 participants) of probiotics for constipation in elderly people indicated that probiotics produced a small but meaningful benefit; the type of bacteria most often tested was Bifidobacterium longum, and the researchers suggested that probiotics might be helpful for chronic constipation in older people as an addition to the usual forms of treatment. The supplied research notes contain an incomplete 2017 review of 7 studies on this topic and do not provide its findings; no further conclusion on that review is stated here. (1)

Irritable bowel syndrome (IBS)

Although some evidence suggests that certain probiotics may improve IBS symptoms, there is not enough evidence to know for sure. According to practice guidelines from the American College of Gastroenterology (2021), there's not enough strong evidence on the effectiveness of probiotics for IBS to recommend their use; the guidelines say the current evidence for this recommendation is very weak, because many different types of probiotics have been studied and most of the studies have been small, with mixed results. A 2022 review and analysis of 10 studies in 757 people with constipation-predominant IBS found that probiotics improved stool consistency but did not help reduce pain or bloating or improve quality of life; the quality of the evidence in the reviewed studies was low. A 2021 review and analysis of 9 studies in 651 children with IBS found that children who took probiotics had less severe and less frequent abdominal pain than those who took a placebo, but different studies used different doses and types of probiotics and it is not clear how the size of the probiotic dose relates to pain in children with IBS. A 2020 review and analysis of 35 studies involving 3,452 people with IBS found that taking probiotics for 4 weeks may help relieve IBS symptoms such as abdominal pain, bloating, and gas, with better results from combination probiotics than single probiotics; because of small study sizes and differences in the types of probiotics and methods used, it is not clear which types of probiotics are the most effective. A 2019 review and analysis of 14 studies in 1,695 people with IBS reported that daily doses of probiotics containing Lactobacillus and Bifidobacterium microorganisms relieved overall IBS symptoms more than daily doses of a single probiotic. (2)

Other conditions described as showing promise

The NCCIH source states that probiotics have shown promise for a variety of health purposes, including prevention of antibiotic-associated diarrhea (including diarrhea caused by Clostridium difficile), prevention of necrotizing enterocolitis and sepsis in premature infants, treatment of infant colic, treatment of periodontal disease, and induction or maintenance of remission in ulcerative colitis. However, in most instances we still don't know which probiotics are helpful and which are not, how much of the probiotic people would have to take, or who would be most likely to benefit. The supplied research notes do not include detailed study findings for these additional conditions. (1)

Before taking probiotics

Do not take / not appropriate for

  • Do not use probiotics in place of medical care for a serious or life-threatening condition. The sources used for this page do not establish any situation in which probiotics are a substitute for treatment of a disease, and the evidence for most uses is weak, mixed, or insufficient. (all products) (1) (3)
  • Do not take a bigger dose than the label recommends. (all dietary supplement products) (3)

Tell your clinician about

  • Tell your health care provider about any dietary supplements you use.
  • Check with your health care provider about the supplements you take if you are going to have any type of surgery.
  • Tell your clinician if you are seriously ill or have a compromised immune system, because the risk of harmful effects from probiotics is greater in these groups.
  • Tell your clinician if the intended user is a premature infant, because cases of severe or fatal infections have been reported in premature infants who were given probiotics, and the FDA has warned health care providers about this risk.
  • Tell your clinician if you have IBS and are considering probiotics, so the options can be discussed together.
(3) (1) (2)

Probiotics dosage and how to take it

  • The sources used for this page do not provide dosing, scheduling, or administration instructions for probiotics. No supplement dose is given by these sources.
  • To take a supplement as safely as possible: tell your health care provider about any dietary supplements you use; do not take a bigger dose than the label recommends; check with your health care provider about the supplements you take if you are going to have any type of surgery; and read trustworthy information about the supplement.
  • If you have IBS, you may have to try a few treatments—lifestyle changes, medicines, probiotics, mental health therapies—to see what works best for you; see what your health care provider recommends.
  • Do not change the dose, product, or regimen based on this page; ask your clinician or pharmacist about the specific product you intend to use.
(3) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3)

Missed dose

Not established by the sources used for this page. These sources do not provide a dosing schedule for probiotics, so no missed-dose rule can be stated. Ask your clinician or pharmacist about the specific product you are using.

Overdose

The sources used for this page do not provide overdose amounts or overdose management for probiotics. If you are concerned about an overdose, a possible reaction, or a product taken by a seriously ill person, a person with a compromised immune system, or a premature infant, contact a healthcare professional or poison-information service promptly. Seek emergency care immediately for severe symptoms. (1) (3)

Probiotics side effects

Probiotics have an extensive history of apparently safe use, particularly in healthy people. However, few studies have looked at the safety of probiotics in detail, so there's a lack of solid information on the frequency and severity of side effects. The risk of harmful effects from probiotics is greater in people who are seriously ill or have compromised immune systems. In people with IBS, probiotics usually have only minor side effects, if any. Most research about the safety of probiotics comes from studies of Lactobacillus and Bifidobacterium; less is known about other probiotics.

Cramping and nausea in people with IBS

What to notice: Cramping and nausea have been reported; in people with IBS, probiotics usually have only minor side effects, if any.

What to do: Discuss persistent or troublesome symptoms with your health care provider rather than changing the product yourself. (2)

No more side effects than patients who did not receive probiotics (antibiotic-associated diarrhea studies)

What to notice: In a 2017 review of 17 studies, patients who were given probiotics had no more side effects than patients who didn't receive them; in children who were otherwise healthy, no serious side effects were observed except for the infection for which they were being treated.

What to do: Discuss any new or worsening symptom with your health care provider. (1)

Infection and acidosis

What to notice: Rarely, more serious side effects have been reported, including infections and acidosis, a potentially life-threatening condition where there is too much acid in the body.

What to do: Seek prompt medical assessment if you develop symptoms that concern you, especially if you are seriously ill or have a compromised immune system. (2)

Severe or fatal infection in premature infants

What to notice: Cases of severe or fatal infections have been reported in premature infants who were given probiotics.

What to do: The FDA has warned health care providers about this risk. If a premature infant has been given probiotics and shows any sign of illness, seek medical care promptly. (1)

Serious warnings

Severe or fatal infection in premature infants — emergency

Symptoms: Cases of severe or fatal infections have been reported in premature infants who were given probiotics.

Action: The U.S. Food and Drug Administration (FDA) has warned health care providers about this risk. Seek emergency medical care for a premature infant who appears unwell after being given probiotics. (1)

Harmful effects in seriously ill people or people with compromised immune systems — urgent

Symptoms: The risk of harmful effects from probiotics is greater in people who are seriously ill or have compromised immune systems. Rarely, more serious side effects have been reported, including infections and acidosis, a potentially life-threatening condition where there is too much acid in the body.

Action: Seek medical assessment promptly if you are seriously ill or have a compromised immune system and develop concerning symptoms; let the clinician you see advise on whether to continue or stop the product. (2) (1)

Interactions

Medicine or testEffectAction
AntibioticsProbiotics have been studied when given along with antibiotics for antibiotic-associated diarrhea and for reducing the risk of C. difficile diarrhea in adults and children receiving antibiotics. The analysis of C. difficile studies concluded that use of probiotics along with antibiotics appears to be safe, except for patients who are very weak or have poorly functioning immune systems.Discuss with your prescriber whether a probiotic is appropriate alongside your antibiotic, and report any new symptoms to your health care provider. (1)
Other treatments for IBS (lifestyle changes, medicines, mental health therapies)If you have IBS, you may have to try a few treatments to see what works best for you; probiotics are one of several options and the evidence for them is not conclusive.See what your health care provider recommends rather than changing or combining treatments yourself. (2)
SurgeryThe sources used for this page state that you should check with your health care provider about the supplements you take if you are going to have any type of surgery.Tell your health care provider and surgical team about any probiotic or other dietary supplement you use before surgery. (3)

Pregnancy, breastfeeding, kidney/liver function, age

Premature infants

Cases of severe or fatal infections have been reported in premature infants who were given probiotics, and the FDA has warned health care providers about this risk. The NCCIH source also lists prevention of necrotizing enterocolitis and sepsis in premature infants among the purposes for which probiotics have shown promise, while stating that much remains to be learned. Decisions for any infant must be made by the treating clinical team. (1)

Children

The 2012 National Health Interview Survey showed that 300,000 children age 4 to 17 (0.5 percent) had used probiotics or prebiotics in the 30 days before the survey. A review of 23 studies of probiotics to prevent antibiotic-associated diarrhea in children provided moderate quality evidence of a protective effect, with no serious side effects observed in children who were otherwise healthy, except for the infection for which they were being treated. A 2021 review of 9 studies in 651 children with IBS found less severe and less frequent abdominal pain than with placebo, but doses and types of probiotics differed between studies. (1) (2)

Elderly people

A benefit of probiotics for antibiotic-associated diarrhea has not been demonstrated in elderly people, and it is uncertain whether probiotics actually don't work in this group or whether no effect was seen because there were only a few studies of people in this age group. For constipation in elderly people, a 2017 evaluation of 9 studies indicated that probiotics produced a small but meaningful benefit, and researchers suggested probiotics might be helpful for chronic constipation in older people as an addition to the usual forms of treatment. (1)

People who are seriously ill or have compromised immune systems

The risk of harmful effects from probiotics is greater in people who are seriously ill or have compromised immune systems, and the C. difficile analysis concluded that use of probiotics along with antibiotics appears to be safe except for patients who are very weak or have poorly functioning immune systems. Discuss any use with the treating clinical team. (1) (2)

Pregnancy and breastfeeding

Not established by the sources used for this page. These sources do not provide information on probiotic use in pregnancy or breastfeeding. The MedlinePlus dietary supplements source notes only that pregnant women can take the vitamin folic acid to prevent certain birth defects in their babies; this is not a statement about probiotics. Ask your health care provider before using probiotics if you are pregnant or breastfeeding. (3)

Monitoring

Before starting

  • Tell your health care provider about any dietary supplements you use.
  • Check with your health care provider about the supplements you take if you are going to have any type of surgery.
  • Read trustworthy information about the supplement.
  • Discuss whether you are seriously ill, have a compromised immune system, or are considering probiotics for a premature infant, since the risk of harmful effects is greater in these groups.
  • Understand that the sources used for this page do not establish which probiotics are helpful for a given condition, how much would have to be taken, or who would be most likely to benefit.

During treatment

  • Watch for side effects; few studies have looked at the safety of probiotics in detail, so there's a lack of solid information on the frequency and severity of side effects.
  • Report cramping, nausea, or any more serious symptoms to your health care provider.
  • If you have IBS, work with your health care provider to see what works best for you among the available options.
  • Do not exceed the dose recommended on the label.
(3) (1) (2)

Storage

Not established by the sources used for this page. These sources do not provide storage instructions for probiotic products. Follow the storage directions on the specific product's label, and ask your pharmacist if you are unsure.

Professional information

Clinician-facing context only. The sources used for this page are US government consumer-facing materials (NIH NCCIH and NLM MedlinePlus). They do not provide dosing, product selection algorithms, or strain-specific efficacy conclusions, and this page does not supply any.

United States

Indication: Any probiotic use

Dose summary: No dose is displayed. The sources used for this page do not provide doses for any indication; for C. difficile risk reduction the types of probiotics that would be most useful, the length of time for which they should be taken, and the most appropriate doses are uncertain, and for IBS it is not clear which types of probiotics are the most effective.

Renal context: Not established by the sources used for this page. No renal or hepatic dosing information is provided; individual assessment is required. (1) (2)

Mechanism of action

Hepatic guidance

Not established by the sources used for this page. No hepatic impairment information is provided.

Overdose note

Not established by the sources used for this page. No overdose amounts or management are provided. (1) (3)

Frequently asked questions

Are prebiotics the same as probiotics?

No, prebiotics aren't the same as probiotics. Prebiotics are nondigestible food components that selectively stimulate the growth or activity of desirable microorganisms. Synbiotics are products that combine probiotics and prebiotics. (1)

Does the evidence show that probiotics work for IBS?

Although some evidence suggests that certain probiotics may improve IBS symptoms, there is not enough evidence to know for sure. According to practice guidelines from the American College of Gastroenterology (2021), there's not enough strong evidence on the effectiveness of probiotics for IBS to recommend their use, and the guidelines say the current evidence for this recommendation is very weak because many different types of probiotics have been studied and most studies have been small, with mixed results. (2)

Are probiotics safe for everyone?

Probiotics have an extensive history of apparently safe use, particularly in healthy people. However, few studies have looked at the safety of probiotics in detail, so there's a lack of solid information on the frequency and severity of side effects. The risk of harmful effects is greater in people who are seriously ill or have compromised immune systems. Cases of severe or fatal infections have been reported in premature infants who were given probiotics, and the FDA has warned health care providers about this risk. (1) (2)

If one probiotic helped with a condition, will another probiotic do the same thing?

Not necessarily. Different types of probiotics may have different effects. For example, if a specific kind of Lactobacillus helps prevent an illness, that doesn't necessarily mean that another kind of Lactobacillus or any of the Bifidobacterium probiotics would do the same thing. (1)

Do probiotics have to be approved by the FDA before they are sold?

Many probiotics are sold as dietary supplements, which don't require FDA approval before they are marketed. Dietary supplement labels may make claims about how the product affects the structure or function of the body without FDA approval, but they aren't allowed to make health claims, such as saying the supplement lowers your risk of getting a disease, without the FDA's consent. If a probiotic is going to be marketed as a drug for treatment of a disease or disorder, it must be proven safe and effective for its intended use through clinical trials and be approved by the FDA before it can be sold. (1)

What is the mechanism of action of probiotics?

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. Probiotics may have a variety of effects in the body, and different probiotics may act in different ways. Probiotics might: help your body maintain a healthy community of microorganisms or help your body's community of microorganisms return to a healthy condition after being disturbed; produce substances that have desirable effects; and influence your body's immune response. (1) (3)

What is the generic name of Probiotics?

The generic name is probiotics. (1) (3)

What class of drug is probiotics?

Probiotics is classed as: Live microorganisms (bacteria and yeasts) used as dietary supplements, food ingredients, or, in some cases, drugs depending on intended use. (1) (3)

References

  1. Probiotics: Usefulness and SafetyNational Center for Complementary and Integrative Health (NCCIH), U.S. National Institutes of Health · United States · dated 2019-08 · accessed 2026-10-13 · source 1
  2. Irritable Bowel Syndrome: What You Need To KnowNational Center for Complementary and Integrative Health (NCCIH), U.S. National Institutes of Health · United States · dated 2023-04 · accessed 2026-10-13 · source 2
  3. Dietary Supplements (health topic)MedlinePlus, U.S. National Library of Medicine · United States · accessed 2026-10-13 · source 3

Brand names by country

Single-ingredient probiotics names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

View brands in additional countries.

This page provides general medicine information, not a diagnosis, prescription, treatment plan, or substitute for advice from your health care provider. The sources used for this page are US government consumer-facing materials, and where they describe the evidence as weak, mixed, tentative, or insufficient this page says so. Dietary supplements are not approved by the US FDA for safety or effectiveness before sale.

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