Every study we read on this question

Trials in people (19)

• 12-week trial in 200 adults with diarrhea-type irritable bowel found better symptom scores
  Randomized trial2024200 peoplePoints to benefit
• 8-week trial in 229 adults with constipation: no clear difference from probiotic vs placebo
  Randomized trial2024229 peopleNo difference
• 8-week trial in 30 adults with constipation-type irritable bowel found less discomfort and bloating
  Randomized trial202430 peoplePoints to benefit
• 4-week trial in 242 adults with constipation found mixed results for a probiotic mix
  Randomized trial2023242 peopleMixed
• 8-week trial in 307 adults with diarrhea-type irritable bowel found lower symptom scores
  Randomized trial2023307 peoplePoints to benefit
• 4-week trial in 79 older adults: no clear difference in main constipation score
  Randomized trial202379 peopleNo difference
• 12-week trial in 46 people with Parkinson's and constipation found more bowel movements
  Randomized trial202246 peoplePoints to benefit
• 6-week trial in 330 adults with irritable bowel: two probiotic strains eased belly pain
  Randomized trial2020330 peoplePoints to benefit
• 4-week trial in 362 women: only the middle probiotic dose beat placebo
  Randomized trial2006362 peopleMixed
• 8-week trial in 75 adults with depression: no clear gut or mood change
  Randomized trial202575 peopleNo difference
• 12-week trial of probiotic plus vitamin D in 35 adults found mixed results
  Randomized trial202535 peopleMixed
• 3-month trial in college students with ADHD found less hyperactivity and better gut symptoms
  Randomized trial2024Points to benefit
• 12-week trial in 57 people with kidney failure: probiotic eased gut symptoms
  Randomized trial202457 peoplePoints to benefit
• 4-week trial in adults with stomach infection on antibiotics: cure rate similar, symptoms better
  Randomized trial2024Mixed
• 6-week trial in 65 adults with diarrhea-type irritable bowel: no clear symptom difference
  Randomized trial202465 peopleNo difference
• Trial in 100 bowel cancer patients after surgery: probiotic mix reduced chemotherapy gut problems
  Randomized trial2023100 peoplePoints to benefit
• Trial in people with constipation, plus mice: one B. longum strain improved symptoms
  Randomized trial2023Points to benefit
• 6-week trial in 44 adults: probiotic did not clearly change bowel symptoms or anxiety
  Randomized trial201744 peopleNo difference
• 4-week trial in 104 adults with irritable bowel: probiotic gave no clear symptom change
  Randomized trial2017104 peopleNo difference

Reviews (8)

• Pooled review of 35 studies in children: probiotics cut diarrhea, not stool frequency
  Pooled review (meta-analysis)2025Mixed
• Pooled review of 91 trials in children with belly pain: no clear probiotic benefit
  Pooled review (meta-analysis)20257,226 peopleNo difference
• Pooled review of 54 trials in irritable bowel syndrome: probiotics improved symptoms
  Pooled review (meta-analysis)2024Points to benefit
• Pooled review of 82 trials in irritable bowel syndrome: some strains improved symptoms
  Pooled review (meta-analysis)202310,332 peoplePoints to benefit
• Pooled review of 43 trials in irritable bowel: B. coagulans ranked best for relief
  Pooled review (meta-analysis)20225,531 peoplePoints to benefit
• Pooled review of 52 trials in children with constipation: no clear benefit from probiotics
  Pooled review (meta-analysis)20224,668 peopleNo difference
• Pooled review of 33 trials in children on antibiotics: less diarrhea with probiotics
  Pooled review (meta-analysis)20196,352 peoplePoints to benefit
• Review of 249 trials: probiotic effects vary by strain; strong evidence for antibiotic diarrhea
  Systematic review2018Points to benefit

Opinion (1)

• Review of Lactobacillus reuteri for gut disease: authors say well evidenced for infant colic
  Opinion or narrative review2023Points to benefit