On AskDrSears.com (click here) we have a complete guide on how to assess and treat this as well as dehydration. Most cases of acute vomiting are caused by intestinal viruses, do not require medical treatment, and do not need to come into the office. If your child is getting moderately to severely dehydrated, or has severe abdominal pain, we should see you that day.
If you think your infant may be vomiting due to an FPIES reaction (onset of multiple vomiting episodes about 2 hours after eating), click here to read about it.