Thanks for your query.
Your child is having diarrhea
which is mostly viral in nature and takes few days to subside.
Give oral rehydrarion solution if he start passing loose stools,give coconut water.buttermilk.curd.banana,boiled potato,rice porridge.
like lactobaccilus for 2 to 3 days and give only home cooked food.
Monitor his hydration status,his activity,urine output.
In case symptoms persist get him evaluated by pediatrician
Wishing your baby good health.