Several primarily inherited disturbances of minerals and trace elements have been discovered within the last 20 years. Secondary disturbances of selenium and zinc induced by dietetic treatment of inborn errors of metabolism and by parenteral nutrition also came to our knowledge recently. Two main types of chronic or primary hypomagnesaemia are known which are caused either by impaired intestinal absorption or by false magnesium handling by the kidneys. In acrodermatitis enteropathica, an autosomal-recessive inherited disease leading to characteristic skin lesions, alopecia and dystrophy, low zinc concentrations of serum, urine and hair are measured. The intestinal absorption of zinc is reduced. In copper metabolism two inherited diseases are known with low serum and usually caerulosplasmin concentrations. In Menkes' steely hair syndrome (trichlpoliodystrophy) an intestinal net malabsorption of copper exists, whereas in Wilson's disease the copper contents of several organs are increased.