Remove offending agent from diet (and maternal diet if patient breastfed)
Volume resuscitation (see: dehydration (peds))
Correct electrolyte abnormalities
Antiemetics prn
If severe (e.g. intractable vomiting, ill-appearing, lethargic, hypotensive)
Methylprednisolone 1mg/kg IV
Epinephrine 0.01 mg/kg IM if shock/hypotension refractory to IV fluids
Methylprednisolone 1mg/kg IV
Epinephrine 0.01 mg/kg IM if shock/hypotension refractory to IV fluids
Food protein-induced enterocolitis syndrome
Esophageal stenosis/atresia
Neutropenic enterocolitis 
Pyloric stenosis
Necrotizing enterocolitis
Intestinal stenosis/atresia
HIV diarrhea
Duodenal atresia