Authors' reply

摘要

Mikhail Kogan says that probiotics are more effective for prevention of diarrhoea if given before or at the start of antibiotic treatment, rather than after. We are not aware of clinical trials that have addressed this issue. In PLACIDE, only patients exposed to antibiotics were eligible12 and, after being provided with trial information, many people wanted to discuss participation with their relatives. The exact start date for antibiotic treatment was known in 2926 patients; the median period of exposure to antibiotics before starting either probiotics or placebo was 3-0 days (IQR 2-0-6-0).