Newborns eat mainly by sucking. When newborns show signs of excessive farting it may be due to occasional crying or swallowing air while sucking milk. If an infant presents with severe vomiting and crying after feeding on breast milk or cow’s milk and the symptoms disappear after stopping feeding, congenital lactase deficiency is considered and prompt medical attention should be sought to avoid dehydration, acidosis, liver and brain damage or even death.