Hi B.Radhika Menon,
usually disturb the normal flora in our intestine. This flora consists of some useful bacteria which help in the process of digestion and absorption.
You can give some Probiotic
along with your antibiotic under medical supervision.
Also get your child examined by a Paeditrician for dehydration
, due to diarrhea
, as dehydration should be immediately taken care of in this age group.
I hope this is helpful to you.