Infant vomiting and spitting up differ in their definitions and the nature of the vomit. 1. Infant vomiting refers to the contents of the esophagus and stomach that gush out of the infant’s mouth and/or nose for various reasons. 2. Infant vomiting refers to milk being spit out of the mouth. The material vomited by the infant can be milk, bile, fecal-like fluid, etc. For infants who have been given complementary foods, the vomit can also be the remnants of complementary foods or digestion. It is important to note that both infant vomiting and spitting up can be caused by physiologic factors or by diseases such as congenital megacolon. And both are prone to the risk of choking and suffocation. When your baby is spitting up or vomiting, you need to go to a regular hospital if necessary.