Outsourcing ideas

Hello, is it normal for a 11 month old baby to experience diarrhea-like illness. I mean nag teteething na kasi sya. We've just consulted a Pedia and she advised us to change into a lactose free formula. Kaso naubos tapos pinabalik namin sa gatas nya. Bumalik na naman din yung pag tatae nya. Pero malakas naman kumain at mag dede specially water.