The literature describing medical aspects on sauna bathing is briefly reviewed. The circulatory effects of heating and subsequent cooling related to sauna bath differ with age, underlying medical condition and use of drugs. The circulatory changes may often be beneficial but can sometimes prove dangerous. More than 2000 sauna bathers were followed for around 20 years in a Finnish population study. The investigators have recently reported health benefits of abundant sauna use for individuals concerning hypertension, ischemic heart disease, dementia and certain pulmonary diseases. Others have recommended the use of sauna for patients with heart failure. Fatal events in sauna are very uncommon and often linked to the use of alcohol, to ischemic heart disease and to bathing alone. Medical conditions in which sauna bathing should be avoided are shortly reviewed. Further studies are urgently needed for illustration of the possible benefit of sauna bath at different medical conditions.