Does eating yogurt prevent antibiotic-associated diarrhoea? A placebo-controlled randomised controlled trial in...

Probiotic capsules have been shown to reduce the incidence of antibiotic-associated diarrhoea in a number of settings. If probiotic yogurt were equally efficacious then it would provide a simple and cost-effective means of preventing antibiotic-associated diarrhoea.

To investigate whether eating live bio yogurt at the time of taking oral antibiotics can prevent antibiotic-associated diarrhoea.

This study was a three-arm (bio yogurt, commercial yogurt, no yogurt) randomised controlled trial with double blinding between the two yogurt arms.

A single primary care general practice surgery in Hingham, Norfolk. The study population included all ages except babies.

Patients aged over 1 year who required a 1-week course of antibiotics were included in the study. There was complete follow up for 369 patients. The intervention was the consumption of 150 ml of live strawberry-flavoured yogurt for 12 days, starting on the first day of taking the antibiotic. Diarrhoea was defined as 'three or more loose stools per day over at least 2 consecutive days' within 12 days of starting the antibiotics.

Of the 120 patients in the no-yogurt group, 17 (14%, 95% confidence interval [CI] = 9.0 to 21.5) developed diarrhoea. Of the 118 given commercial yogurt, 13 (11%, 95% CI = 6.6 to 17.9) developed diarrhoea; nine of the 131 patients (7%; 95% CI = 3.7 to 12.5) given bio yogurt developed diarrhoea (P = 0.17).

Overall, this study failed to demonstrate that yogurt has any effect on antibiotic-associated diarrhoea.