Rapid intravenous injection of 4 mL/kg body weight of a 7.5% hypertonic sodium chloride solution immediately increases intravascular osmotic pressure and intravascular volume after haemorrhage. This 'small volume resuscitation' rapidly improves blood pressure and microcirculatory perfusion in patients with hypovolaemic shock after large blood losses. Pathophysiological findings as well as practical application approaches are described. Small volume resuscitation is an effective and economic method in the first-line treatment of acute haemorrhagic shock.