Children ( aged 1-12years ) prescribed antibiotics , were randomised to receive 200g/day of either yogurt ( probiotic ) containing Lactobacillus rhamnosus GG ( LGG ) , Bifidobacterium lactis ( Bb-12 ) and Lactobacillus acidophilus ( La-5 ) or a pasteurised yogurt ( placebo ) for the same duration as their antibiotic treatment .