There is a reduction in oxygen consumption during hemorrhagic shock, and it has been suggested that this correlates with mortality. Recent data indicate that the consumption of oxygen may depend on its diffusion from the erythrocytes to the mitochondria; thus, enhancing this rate might increase tissue oxygen extraction during hypovolemia. Crocetin, a carotenoid compound which has been shown to increase oxygen diffusivity, was used in rats bled 40% of their blood volumes, and resulted in increased whole-body oxygen consumption and survival rates. Magnetic resonance spectroscopy data also indicate that crocetin increased oxygen uptake by muscle. Other factors which might account for these results, such as possible effects of crocetin on red cell deformability and mitochondrial respiration rates, were also investigated, but the mechanism of action seems to be related to the increased diffusion of oxygen through plasma.