Probiotics are available in many different species and strengths. Some studies suggest probiotics may help with certain types of diarrhea, but others indicate they have little effect.
Probiotics are live microorganisms, such as bacteria and yeasts, that have some kind of positive effect on the body. Scientists are working to learn more about how probiotics benefit health and how they interact with the human microbiome.
The Food and Drug Administration (FDA) has not yet approved probiotics as a treatment for any health condition, including diarrhea.
This article examines whether people should use probiotics for diarrhea. It also discusses which types of probiotics could be beneficial, who can take them, and the potential side effects and risks.
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Acute infectious diarrhea
An older 2010 Cochrane review assessed 63 previous trials involving 8,014 participants. It found that probiotics reduced the duration of diarrhea by approximately 25 hours in comparison to control groups.
Probiotics also decreased the risk of diarrhea lasting for 4 days or more by 59% and resulted in one fewer loose stools 2 days after taking them.
However, when Cochrane updated the review in 2020, with evidence from 82 studies with 12,127 participants, the authors reached the opposite conclusion.
They used larger trials with a lower risk of bias than the first review. They concluded that probiotics likely make little or no difference to the risk of diarrhea lasting more than 48 hours and that the evidence for probiotics shortening the duration of diarrhea was weak.
According to the
A 2021 study found that compared with a placebo, yogurt containing the probiotic Bifidobacterium lactis BB-12 helped protect against changes in gut bacteria that can lead to antibiotic-induced diarrhea.
Traveler’s diarrhea is a common illness people can get when traveling abroad. A 2018 meta-analysis of 11 studies concluded that probiotics may significantly reduce the risk of travelers’ diarrhea, but a 2019 review of 12 studies found that only S. boulardii CNCM I-745 was particularly effective.
However, the authors noted that more research was necessary to explore probiotic strains and their effect on traveler’s diarrhea.
If a person has one of the above conditions that cause diarrhea, the following species of probiotic could have a positive effect:
- S. boulardii: This beneficial species of yeast has evidence supporting its use for traveler’s diarrhea and
- Lactobacillus: L. rhamnosus, L. casei, and L. acidolphilus have evidence to support their use for antibiotic-associated diarrhea and acute diarrhea.
- Bifidobacteria: This family of bacteria is often present in dairy products, such as yogurt, which may help reduce the risk of antibiotic-associated diarrhea.
That said, it is important to note that no probiotic is an approved treatment for diarrhea, as scientists are still learning about them. If the symptoms worsen or keep recurring, a person should speak with a doctor.
Probiotics may not be safe for everyone.
For people with no other health conditions, probiotics with a long history of use in foods are
However, people with severe illnesses or compromised immune systems should not take probiotics due to the risk of an opportunistic infection.
It may also be unsuitable to take probiotics if a person has certain digestive conditions. For example, a
The researchers advise proceeding with caution if a person:
- has slow digestion, or dysmotility
- takes opioids or other drugs that slow digestion
- takes proton pump inhibitors
In its 2020 guidelines, the American Gastroenterological Association also recommends against using probiotics for acute infectious diarrhea in children.
When trying probiotics, it is important to consider:
Companies list the dosage of their probiotics in colony-forming units (CFUs). Probiotic supplements usually contain
Studies investigating the effect of probiotics on diarrhea have CFU ranging between 10–100 billion CFU per dose. A healthcare professional can help an individual select the most appropriate probiotic strain and dosage.
Some people prefer to start with a low dose and work up to the recommendation from a doctor or the product label.
In some situations, the timing of probiotic doses may influence their effectiveness.
For example, evidence suggests that people with antibiotic-associated diarrhea benefit most when they start probiotics within
If a person is traveling somewhere where there is a high risk of traveler’s diarrhea, they may choose to begin taking a probiotic that is proven to help prevent it shortly before arrival.
Any side effects of probiotics are
If symptoms significantly worsen or keep returning, this may not be due to the probiotics. Anyone with the following symptoms should speak with a doctor:
Research examining the use of probiotics for diarrhea have conflicting results. Some studies suggest that certain probiotics may be helpful for specific causes of diarrhea. Other studies have concluded that probiotics probably have little to no effect.
If a person wants to try probiotics for diarrhea, it is important that they consult a doctor to determine the cause. In some cases, the cause may be unrelated to gut bacteria, and probiotics may not be necessary.
A person should seek medical attention if they have recurring or severe diarrhea.