The book examines acute disorders of the water, electrolyte and acid-base balance that occur in surgical and therapeutic patients. Issues of diagnosis and treatment of acute imbalance of water and electrolytes in shock, peritonitis, acute intestinal obstruction, acute pancreatitis and other pathological conditions are discussed in detail. Much attention is paid to infusion therapy: the choice of the qualitative composition and volume of infusion media, the method of infusions and complications, control of the overall balance and sectoral distribution of fluid in the body. The role of acute disturbance of the balance of water and electrolytes in the formation of typical reactions of central and peripheral hemodynamics is shown. The book is designed for surgeons, therapists, anesthesiologists-resuscitators.