The academic study of body temperature began in 1868. Since then, a variety of thermometers have been developed for clinical use. A working knowledge of these different thermometers, the various sites for taking temperature, and the normal range of body temperatures, is essential. As the pathogenesis of fever is being elucidated, and the cytokines involved identified, the risks and benefits of fever to the organism are becoming better understood. The importance of recognising diagnostic fever patterns should be stressed. Acetaminophen (paracetamol) and ibuprofen are accepted as the standard medical treatments for fever.