This Cochrane Review assessed the effectiveness and safety of probiotics for preventing acute upper respiratory infections (URTIs).

First, the details.

  • 14 studies were included in this review.
  • Data for a meta-analysis were available from 10 studies, which involved 3451 participants.

And, the results.

  • Probiotics were better than placebo for following parameters.
    • Number of participants experiencing at least 1 or 3 episodes of acute URTI
    • Fewer episodes of acute URTI
    • Reduced antibiotic prescription rates for acute URTIs
  • Probiotics and placebo were similar in the average duration of an episode of acute URTI.
  • Adverse events were similar between probiotics and placebo.
    • Side effects of probiotics were minor, with gastrointestinal symptoms a common occurrence.

The bottom line?

Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute URTIs and antibiotic use.

Probiotics may be better than placebo for preventing acute URTIs. However, the results have some limitations and there were no data for older people, according to the reviewers.

The National Center for Complementary and Alternative Medicine tells us, “Probiotics are live microorganisms (in most cases, bacteria) that are similar to beneficial microorganisms found in the human gut. They are also called “friendly bacteria” or “good bacteria.” Probiotics are available to consumers mainly in the form of dietary supplements and foods. They can be used as complementary and alternative medicine (CAM).”

9/22/11 20:41 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.