The evolution of an effective program for the treatment of frostbite has been beset with unusual difficulties. For one thing, we have inherited a literature weighty with authority but largely based upon folklore and arm-chair philosophy rather than upon sound deductions from objective clinical and experimental data. It has been necessary, therefore, not only to attempt to develop new rational methods based upon controlled observations, but at the same time to overthrow erroneously conceived, but firmly established, dogma. For another thing, proper evaluation of therapy in human frostbite has been particularly difficult because of the relative dearth of material for study in times of peace and the impediments to careful clinical experimentation imposed by the exigencies of war. At the same time the variable character of the injury and the impossibility of reasonably accurate early prediction of the eventual outcome in any given case make requisite ample clinical material and its most careful study.Finally, though animal experimentation has the advantage of providing limitless numbers of subjects for study and of permitting adequate control observations, it has thus far proved to be an apparently reliable guide to treatment only in relation to the prevention of gangrene. It has added nothing to the management of the various vasomotor disturbances which constitute the commonest sequelae in man. The treatment of these sequelae in man is, to be sure, not nearly so difficult a problem as the early management of frostbite and the prevention of tissue damage. Animal experimentation, furthermore, has made possible invaluable contributions to our understanding of the functional pathology of frostbite and gives promise of adding new information about acclimatization and prophylaxis.In spite of the difficulties which have been mentioned real progress has been made in recent years in bringing about a better comprehension of the basic problem and a more rational approach to treatment. In this communication I shall limit my remarks to true frostbite and the related less severe injuries resulting from exposure to more or less dry freezing temperatures.