Hello \Thank you for placing your query with Health Care Magic The most important thing right now would be to get your son rid of his vomiting. A proper anti-emetic (drugs against vomiting) should help. You should consult a pediatrician for proper prescription. If still it is difficult to establish a good intake and your child develops dehydration he may need fluids via injections. Watch out for his urine output. It should not be decreased. Most common cause for diarrhea in young children is viral and so it is not advised to start antibiotics but i suggest you consult your pediatrician so that he can rule out any bacterial infection (usually suggested by blood or mucous in stool along with fever). A stool examination will also help. I suggest you use standard Oral Rehydration Solution (ORS) for treating his diarrhea. Hope that helps. God bless you