Digestion/Immunity/Mood

Probiotics

Live microorganisms that support digestive and immune health, most beneficial during antibiotic use or for irritable bowel syndrome.

Probiotics

Live microorganisms that support digestive and immune health, most beneficial during antibiotic use or for irritable bowel syndrome.

score

evidence

Caution

risk

Proven Benefits

01Reduces antibiotic-associated diarrhea

02Prevents severe diarrhea (C. difficile)

03Relieves irritable bowel symptoms (IBS)

04Reduces respiratory infections

05May prevent traveler's diarrhea

06May reduce anxiety or depression

Chemical Forms

Recommended

Multi-strain blends (10+ billion CFU)
Saccharomyces boulardii for antibiotic-associated diarrhea
Lactobacillus rhamnosus GG for travel and immunity
Bifidobacterium infantis 35624 for IBS

Avoid

Unrefrigerated live cultures past expiry
Products without strain-level identification
Gummies with high sugar and low CFU counts

Expert Note

Efficacy is highly strain-specific; for example, Saccharomyces boulardii CNCM I-745 has strong RCT evidence for antibiotic-associated diarrhea, whereas generic Lactobacillus acidophilus may not. Products listing only genus or species without a specific strain code cannot be matched to clinical evidence, and heat-unstable formulations may lose potency before consumption.

Protocol

Amount

10-50 billion CFU

Frequency

Once or twice daily

When

With a meal to improve survival through gastric acid; separate from antibiotics by 2+ hours unless taking a yeast-based probiotic such as Saccharomyces boulardii.

Condition-Based Dosing

Antibiotic-associated diarrhea prevention

10-20 billion CFU daily of Saccharomyces boulardii or L. rhamnosus GG, starting with antibiotic course— Continue for 1-2 weeks after antibiotics finish.

IBS symptom management

1-10 billion CFU daily of Bifidobacterium infantis 35624 or multi-strain blend— Trial for 4 weeks before assessing response; efficacy varies by IBS subtype.

Upper respiratory infection prevention

5-10 billion CFU daily of L. casei or L. rhamnosus GG— Best evidence in children and athletes; modest benefit in healthy adults.

General digestive maintenance

5-10 billion CFU daily of mixed Lactobacillus/Bifidobacterium— Lower doses may suffice for healthy adults with balanced diets.

Safety & Limits

Upper Safe Limit

No established UL; doses up to 100 billion CFU/day studied without serious harm in healthy adults.

Cycling

Safe for continuous use

Contraindications

Central venous catheter or ICU patient — risk of bacteremia/fungemia

Severe acute pancreatitis — some trials show increased mortality

Immunocompromised (e.g., chemotherapy, transplant) — infection risk

Short bowel syndrome or open surgical wounds — translocation risk

Premature infants — case reports of sepsis

Avoid Combining With

✕Antibiotics (take bacterial probiotics 2+ hours apart; yeast-based S. boulardii does not require separation)
✕Hot beverages or very warm foods (heat kills live cultures)
✕Alcohol in large amounts (may reduce viability and disrupt colonization)
✕Bismuth subsalicylate and other anti-diarrheal agents (may reduce colonization speed)

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