Hello!!!

I have a 4 month child with cah. I have a question. My son won’t stop vomiting and I don’t know why. He was in the hospital for 2 weeks because they were checking if he would stop vomitng and they gave him like three medicines for the vomit and they changed his milk too. They say that is because  amybe he has reflex, but I think is because of his medicine he is on hidrocortisone and  flurinef. I don’t know what to do. Any suggestions???