My Son Is 16 Months Old..he Frequently Starts With Diarrhea

My son is 16 months old..he frequently starts with diarrhea and doc gives enterogermis motion stood but fever increases to 100 to 102..sometimes he keeps his tongue out and after giving antibiotics the fever reduces.this thing happened three times in span of 45 days..Iam bit worried..doc this time has given for stool test