Vomiting in the infant is a common and nonspecific symptom of a multitude of disorders that can range from mild, self-limited illnesses to severe, life-threatening conditions. Less common causes of vomiting include inherited metabolic defects and diseases of endocrine and cardiovascular system. Disorders of proteins metabolism (e.g. phenylketonuria, maple syrup urine disease, urea cycle disorders, organic acidemias) are uncommon but can manifest with vomiting in newborns and younger infants. Infants with galactosemia can develop symptoms (recurrent vomiting) in the first few days after initiating milk feeding. Symptoms associated with lipid metabolism disorders (e.g. fatty acid beta-oxidation defects or Smith-Lemli-Opitz syndrome) in some cases can concern the digestive system. Emesis is also one of the most frequent symptoms associated with hypercalcaemia due to vitamin D intoxication. Salt wasting forms of endocrinological diseases (with metabolic acidosis and electrolyte disturbances: high potassium and low sodium), including congenital adrenal hyperplasia due to 21-hydroxylase deficiency, are often associated with emesis and severe dehydration. Recurrent vomiting can rare be caused by a variety of heart diseases, e.g. myocardial infarction, myocarditis. Congenital defects of the aortic arch, also known as vascular rings, can cause compression of the oesophagus and result in symptoms like dysphagia or vomiting. Clinical signs of hypertensive crisis in infants (usually due to renal vascular abnormalities, acute or chronic renal parenchymal diseases and aortic coarctation) very often include nausea and vomiting as well.