Soon after the discovery of radium, a school of practitioners arose who were interested primarily in the physiological rather than the tumoricidal powers of this new radioactive element. This treatment philosophy was called "mild radium therapy" and involved the oral or parenteral administration of microgram quantities of radium and its daughter isotopes, often as cures for rheumatic diseases, hypertension, and metabolic disorders. Manufacturers of patent medicines responded to this market by producing a variety of over-the-counter radioactive preparations including pills, elixirs, and salves. One such nostrum was Radithor, a popular and expensive mixture of radium 226 and radium 228 in distilled water. Radithor was advertised as an effective treatment for over 150 "endocrinologic" diseases, especially lassitude and sexual impotence. Over 400,000 bottles, each containing over 2 muCi (74 kBq) of radium, were apparently marketed and sold worldwide between 1925 and 1930. The death of the Pittsburgh millionaire sportsman Eben M. Byers, who was an avid Radithor user, by radium poisoning in 1932 brought an end to this era and prompted the development of regulatory controls for all radiopharmaceuticals.