The purpose of the study was to assess the toxicity of various short-chain alcohols using the thermoregulatory system of the rat as an endpoint. Male Fischer rats developed significant hypothermia following acute administration (i.p.) of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, or 2-butanol. The hypothermic responses to the six alcohols all showed similar bimodal responses characterized by a threshold dose below which no change in body temperature occurred, and a suprathreshold regression with increasing dose causing greater hypothermia. Relative efficacy of the alcohols was compared using both the threshold dose to cause hypothermia and the dose which would cause body temperature to decrease by 1 C. Both measures gave the progression of toxicity from least to most potent of: methanol