A classification of the chief causes of diar- rhoea and vomiting in infancy is given below.Diagnosis of the cause of vomiting in infancy can only be arrived at after a careful consideration of the signs and symptoms. Vomiting IL ObstructiveCongenital hypertrophic pyloric stenosis.Congenital atresia or stenosis of the intes- tine.Oesophageal stenosis.Achalasia of cardia of stomach.Intussusception.II.Non-Obstructive Overfeeding.Due to aerophagy.Rumination.Habit vomiting.Allergic vomiting.Vomiting secondary to infection (often associated with diarrhoea).Vomiting and Diarrhoea I. Gastroenteritis.Infection of the bowel with pathogenic organisms.II.Due to dyspepsia.III.Secondary to parenteral infection.