Is yoghurt helpful for antibiotic-associated diarrhoea?

Jack, a health conscious 48-year-old man, came in a while ago with cellulitis following a small injury.

As I printed his antibiotic prescription, he mentioned that he had previously suffered from diarrhoea with antibiotics and asked whether eating yoghurt would help.

I recently had a personal stake in this question as I was on antibiotics myself. I realised on reflection that I had hitherto given vague answers to my patients.

Critical appraisal

We should focus on methods before results. Using the critical appraisal sheet from the Centre for Evidence Based Medicine at the University of Oxford:³

PICO

Participants: who was studied?

407 patients aged over one year, presenting to