Scientists reviewed 47 studies with over 15,000 people to see if probiotics (good bacteria) can prevent a dangerous type of diarrhea caused by antibiotics. When people take antibiotics, it can kill good bacteria in their gut, allowing harmful bacteria called C. difficile to grow and cause serious diarrhea. The research found that probiotics may cut the risk of this dangerous diarrhea in half. For every 65 people who take probiotics with their antibiotics, one case of this serious infection might be prevented. The probiotics appeared safe with few side effects.

The Quick Take

  • What they studied: Whether taking probiotics (good bacteria supplements) while on antibiotics can prevent a dangerous type of diarrhea caused by C. difficile bacteria
  • Who participated: Over 15,000 adults and children from 47 different studies who were taking antibiotics for various medical reasons
  • Key finding: Probiotics may cut the risk of dangerous antibiotic-related diarrhea in half, from about 3 cases per 100 people down to 1.6 cases per 100 people
  • What it means for you: If you’re taking antibiotics and not immunocompromised, probiotics might help protect your gut, but talk to your doctor first since the benefit is small

The Research Details

This was a comprehensive review that combined results from 47 separate studies, including 8 new studies with 4,595 participants. All studies were randomized controlled trials, meaning participants were randomly assigned to receive either probiotics or a placebo while taking antibiotics. The researchers looked at different types of probiotics, doses, and patient populations to get a complete picture of how well these supplements work.

Combining many studies gives us more reliable results than looking at just one study. With over 15,000 participants total, the researchers could detect even small benefits that might be missed in smaller studies. This type of analysis helps doctors make better recommendations based on the strongest available evidence.

The studies came from the respected Cochrane database, known for high-quality medical reviews. However, about 30% of the studies didn’t have published protocols, and 28 studies had financial ties to probiotic companies, which could influence results. The researchers accounted for these limitations in their analysis.

What the Results Show

Out of 13,179 participants across 38 studies, probiotics reduced C. difficile-associated diarrhea from 3.2% in the control group to 1.6% in the probiotic group. This represents a 50% relative reduction in risk. In practical terms, this means for every 65 people who take probiotics with antibiotics, one case of this dangerous diarrhea might be prevented. The effect was consistent across different age groups and settings, though the absolute benefit remains small since the infection is relatively uncommon to begin with.

Probiotics also appeared to reduce regular antibiotic-associated diarrhea and seemed safe with fewer adverse events compared to placebo groups. There was no significant difference in hospital stay length between groups. The benefits appeared regardless of whether people were in the hospital or outpatients, and worked for both adults and children.

This updated review included 8 new studies since the last version, strengthening the evidence that probiotics may help prevent C. difficile infections. The findings are consistent with previous research showing probiotics can help maintain gut health during antibiotic treatment, though the effect size remains modest.

The biggest limitation is that many studies had ties to probiotic companies, which could bias results toward showing benefits. Also, the studies used different probiotic strains and doses, making it hard to know which specific products work best. The research mainly included people who weren’t severely immunocompromised, so results may not apply to everyone.

The Bottom Line

For healthy adults and children taking antibiotics, probiotics may provide a small protective benefit against dangerous C. difficile diarrhea with minimal risk of side effects. However, the absolute benefit is small - you’d need to treat 65 people to prevent one case. The evidence suggests probiotics are likely safe for short-term use in non-immunocompromised patients.

People prescribed antibiotics, especially those in hospitals or healthcare settings where C. difficile is more common, might benefit most. However, people with compromised immune systems should be cautious and consult their doctor, as this research didn’t include many immunocompromised participants.

The protective effects would need to occur during and shortly after antibiotic treatment, as this is when the risk of C. difficile infection is highest. Benefits would be most relevant during the course of antibiotic therapy and for several weeks afterward.

Want to Apply This Research?

  • Track antibiotic courses and any digestive symptoms, including bowel movement frequency, consistency, and any abdominal discomfort during and after antibiotic treatment
  • Consider discussing probiotic supplementation with your healthcare provider when prescribed antibiotics, and log any probiotic use alongside antibiotic courses
  • Monitor digestive health patterns during antibiotic treatments over time to identify personal risk factors and response to probiotic supplementation

This information is for educational purposes only and should not replace professional medical advice. Always consult your healthcare provider before starting probiotics, especially if you have underlying health conditions or are immunocompromised. Individual results may vary, and probiotics may not be appropriate for everyone.