The authors examined in 45 patients with multiple injuries total serum cholesterol levels and the packed cell volume on admission, 24 hours and 48 hours after injury. The cholesterol level in these patients declined as compared with a control group to 0.61 on admission of the patient (on average 102 min. after injury) and to 0.51 and 0.53 24 and 48 hours after injury, while the packed cell volume declined to 0.76 on admission and to 0.64 24 and 48 hours after the injury. The lose correlation between cholesterol and the packed cell volume (r2 = 0.27) suggests the part played by another mechanism of development of hypocholesterolaemia in patients with multiple injuries than mere haemodilution. In eight patients who died no correlation with hypocholesterolaemia was found.