Hypothermia is generally considered to be a special technique of the surgeon and anesthetist because of the increasing utilization of lowered body temperature in cardiovascular and neurosurgery. Twenty years ago, however, the internist was utilizing hypothermia to treat the intractable pain of terminal cancer,1and since that time it has been used experimentally in the treatment of schizophrenia, leukemia, and morphine addiction.2Routinely during winter months in northern hospitals the medical staff is faced with the problem of accidental hypothermia occurring as a result of exposure to cold. It is the purpose of this paper (1) to review the physiologic changes known to occur at subnormal body temperatures, (2) to present the clinical and pathological data from the cases of accidental exposure treated at this hospital over the past 12 years, and (3) to evaluate critically the management and therapy of the hypothermic state occurring as a result