Supplementing a recent review 'Health effects of high radon environments in Central Europe: another test for the HLNT hypothesis [1]', this review of medical radon applications (in particular for the treatment of painful degenerative joint and spine diseases) covers mainly the first century of large-scale use and scientific studies on this subject since the discovery of radon. Most of the studies and experiences originated in Europe, in particular Germany, Austria, and the former USSR. They have in common that they are not well known in the anglophonic scientific literature, where radon therapy is still frequently considered a placebo-type 'traditional medicine', and not be compared with the drugs such as non-steroid antirheumatics. However, based on the substantial experiences as reflected in more than one thousand papers, mostly in peer-reviewed scientific journals, on this subject, radon therapy by inhalation or baths has been established as an evidence-based effective treatment not only by empirical experience in different times and cultures, but also in randomised clinical double-blind studies. It should be further explored as an effective alternative to the use of pharmaca. Unlike radon, drugs cause serious side effects, with more than ten thousand annual casualties. The benefits in the adequate use of low-dose radon exposures far exceed the hypothetical lung cancer risk attributed to the inhalation of low radon concentrations. Further research could provide better understanding of the mechanism of the stimulating radon effects on the body's defence systems.