Probiotics are helpful bacteria of healthy gut and have shown potential in reducing allergy. A double-blind, randomized placebo-controlled clinical trial studying the effects of 6 months probiotics supplementation from birth on allergic disease and sensitization up to 2 years of age had been conducted. This study aims to assess the longer term beneficial effects of this form of intervention on the incidence of allergic disease and sensitization at 5 years of age by extending the follow-up period.