The PubMed database contains about eighty scientific papers on crenobalneotherapy (i.e., medical balneology or spa therapy) published in the last three years, mostly in journals with an impact factor. These studies focus on the actions of thermomineral products (waters, muds, gases, steam) on biological systems (immune system, antioxidant system, cytokine networks, nociception, etc.). Hot mineral waters can have an action on the circulatory system. Ingested mineral water can act on carbohydrate, lipid and mineral metabolism. Dermocosmetologic mineral products have shown real benefits. Medical benefits of thermal treatment have been observed in patients with rheumatic conditions, psoriasis, venous insufficiency, ENT conditions, gynecolgical disorders, and anxiety. Unfortunately, many publications in this area suffer from methodological flaws. Clinical investigations of thermal medicine encounter dificulties of a methodological and financial nature, and problems of patient recruitment. The aim of the French thermal research institute is to provide support and advice for teams wishing to conduct well-designed controlled trials.