Our interactive computer model for the oxygen transport uses demographic physiologic data combined with individual clinical and laboratory data to simulate various physiological and pathophysiological states. Besides for teaching purposes it can be also used for integration of multiple clinical and laboratory measurements. Thus, the model enables to to predict the arterial oxygen saturation and blood CO₂ levels by interactively changing different parameters that are accessible from clinical and laboratory measurements or alternatively replaced by the corresponding demographic data. In the model it is possible to vary the gas composition and the barometric pressure, alveolar ventilation, diffusion capacity of the lungs, blood hemoglobin concentration, plasma protein concentration (both affect pH), blood perfusion of different tissues (so far we use 6 different tissues), specific tissue metabolism and the tissue capillary density. It is possible to change the acid-base status by adding bicarbonate and nonvolatile acids, and thus to change base excess. The model is based on known kinetic principles to describe transport of blood gases in human body from the outer atmosphere to different tissues. It is composed of four compartments for transport of blood gases (O₂ and CO₂): airways, alveolo - capillary interface, the blood and the blood vessels, and the Krogh cylinder for blood gas exchange in tissues, including chemical regulation of breathing. It is a steady state model, and does not provide transients. The components of the model were validated using published data from different experiments, such as those of Siggaard Anderson for the acid-base status of the blood.