Man living at high altitudes is constantly subjected to a stress, caused by the low oxygen tension in the air he breathes, which brings into play a series of mechanisms that permit him to adapt to his environment. This is the phenomenon of acclimatization to altitude,1in which lowered saturation of the arterial blood, resulting from the reduced partial pressure of oxygen, stimulates the hematopoietic system to produce the well-known polycythemia of high altitude.2 The chronic hypoxia affects not only the hematopoietic system, but other organs and systems as well.3,4The liver, site of control of many intermediate metabolic processes, consumes more oxygen than most other organs, so that anoxia, of any origin, may cause definite changes in its function5and structure.6In addition, functional alterations in other systems, caused by hypoxia, may affect liver function.7 Studies of hepatic function in acute hypoxia8