[The treatment of acute dehydration (author's transl)]

In infants and children acute dehydration is mainly caused by gastroenteritis with vomiting and diarrhoea, and by feeding failures. Since in the German speaking literature very different therapeutic regimens for rehydration are discussed the principles of oral and parenteral treatment are described. The rational therapy is based on the knowledge of physiology and pathophysiology of water and electrolyte metabolism. Therefore a few basic aspects are described, i.e. compartments of body fluids, turnover rates, the balance, types of dehydration, concentration of electrolytes in body fluids and their relevance to dehydration. Special problems exist in the treatment of hypertonic dehydration. In order to avoid cerebral edema the rehydration should not be attempted quickly with very hypotonic salt solutions, but should be performed with a 1/2--1/3 isotonic Ringer-lactate solution and early begin of potassium substitution over a period of 48 h.