Vomiting is described as forceful expulsion of gastric contents via the mouth.1,2
It should not be confused with reflux which involves the involuntary retrograde passage of gastric contents into the esophagus, with or without regurgitation.3
An episode of vomiting will generally resolve by itself 6 to 24 hours after it starts. A baby shouldn't need any particular medical treatment; however, it is important to ensure that they receive plenty of fluid to avoid dehydration.