This blog accompanies the new YouTube video “In Czechia, They Prescribe Radon as a Cure. And it was weird.” – check it out now.
Introduction
I am staying at the Radium Palace in Jáchymov, Czech Republic, where you can bathe in radioactivity. It is all perfectly legal. I wanted to find out what it would do to me – how I would feel, what would happen.
The experience was clinical. Twenty minutes in a radon bath. Half a millisievert. Tingly fingers and toes. And, as the RadiaCode confirmed, radioactive swimming trunks.
Why Jáchymov?
Jáchymov (German: St. Joachimsthal) is a spa town in the Ore Mountains of northwest Bohemia. It has been a centre of mining, science, and radioactivity research for over 500 years.
The Discovery of the Radon Spring
In 1864, miners accidentally hit a spring in the Svornost mine. They flooded the sixth level, but discovered that the water was miraculous – soaking injured and inflamed areas was cured “just like that.”
The water was hot because of radioactive decay underground. It was also radioactive, because when uranium decays it decays into radium, which then decays into radon gas. That gas gets into the water, and the water carries it to the surface.
The Curies and Jáchymov
In 1898, Marie and Pierre Curie were looking for uranium samples to do science with. They found the Jáchymov uraninite to be more radioactive than anything else they had tested. It is from this ore that they discovered the elements radium and polonium.
Radium and polonium are far more radioactive than uranium. Coupled with Henri Becquerel’s discovery of radioactivity in 1896 and Ernest Rutherford’s discovery of the gas radon in 1899, this opened up the age of nuclear science.
The First Radon Baths
Putting two and two together, the magical healing properties of the Svornost radon water were harnessed in the first radon baths in 1906. A former miner called Josef Prenning – nicknamed “Thunderbolt” – carried 40 litres of water a time from the mine to the baths. Not an easy task.
Demand outstripped poor Josef, and a year or two later a 4km pipeline was installed, delivering water from the mine to the burgeoning spa area. The fame and promise of the new wonder-cure attracted visitors such as Richard Strauss and King Edward VII.
The Radium Palace
In the 1920s, the Radium Palace was launched close to the glass factory. It offered visitors decadence and luxury, built around the promise of radon as a cure-all. Spas went from being places where the well-to-do relaxed and recuperated, to science-backed, cutting-edge futuristic treatment for all ails.
The hotel was one of the most modern in Europe. In 1929, the owner Urban significantly renovated the surroundings – building a terrace with balustrades, an underground bar, and a tennis court.
Notable visitors included Marie Curie-Sklodowska (who visited in 1925), President T. G. Masaryk, Richard Strauss, Egyptian King Fuad, Karl May (the famous adventure writer, who was the “first celebrated guest” of the spa in 1908), Karel Čapek (creator of the word “robot”), and Václav Havel.
What Makes Jáchymov Special
The water in Jáchymov is the most radioactive of all the European spas – 2.5× the next strongest spa in Europe. The Svornost mine is still operational, drawing from four different springs to supply dozens of spas from 700m below the surface.
The water itself is extraordinary – 13,000 years old. Trapped underground since the last ice age, it has been percolating through uranium-rich rock for millennia, absorbing radon gas as it goes. When it surfaces at the spa, it is carrying that ancient radioactivity with it.
The Svornost mine has been operating since 1530 – over 490 years of continuous mining history. The name “Svornost” (Concord) was chosen to commemorate the settling of mining rights disputes. Originally mined for silver, then cobalt, arsenic, and bismuth. In the 19th century, it became a source of radium ores for dyeing glass and porcelain. Post-WWII, it peaked in the 1950s as a uranium source. Since 1964, it has supplied therapeutic radon water to the Jáchymov spa.
The Radium Craze and Its Backlash
Around the turn of the 20th century, for about 30 or 40 years, radioactivity was seen as the cure for everything. From a dicky tummy to impotence – it was the cure for everything. Products involving radium, radon, and even thoron (the “posh gas” – radon and thoron are the same thing, just different isotopes) were everywhere.
Around the 1920s and 1930s, people started to realise that radioactivity – especially in things like radium – was not a good thing in most cases. The famous story of the Radium Girls – girls who painted the dials of clocks with radium paint and became seriously ill – brought the dangers into public consciousness. By the 1950s, radium and radon were widely seen as dangerous.
The Worm Turns: Radiation Hormesis
Now we come to the 21st century, and the worm is starting to turn. There has been 500–600 years of people feeling better after having a radon bath, and that cannot just be chance coincidence. There must be something in it.
The scientific explanation is the radiation hormesis hypothesis – the idea that a small dose of radiation encourages the body to repair itself. Low-dose exposure triggers cellular repair mechanisms that might not otherwise be activated. But this is no longer just a hypothesis. A growing body of peer-reviewed clinical evidence supports the therapeutic efficacy of radon baths, particularly for rheumatic diseases.
The Evidence
RAD-ON02 (2024) – A double-blind, randomised controlled trial published in Frontiers in Immunology enrolled 116 patients and compared radon spa treatment against warm water alone. The results were clear: the radon group was significantly superior to the control for pain reduction at weeks 4–24 and at 6-month follow-up (p < 0.001). No side effects were reported.
Meta-analysis (2025, PMC12904653) – A systematic review of 8 studies encompassing 2,152 patients found a large effect size (Hedges’ g = 0.99, p = 0.0004) for radon therapy in the treatment of rheumatic conditions.
Becker et al. (2004) – In International Journal of Radiation Biology, Becker and colleagues reviewed 100 years of radon therapy, documenting its use across Europe and the mechanisms by which it exerts therapeutic effects.
Falkenbach et al. (2005)– Published in Rheumatology International, this systematic review and meta-analysis of five randomised controlled trials (338 patients) found that while no significant difference was apparent immediately after treatment, radon therapy showed significantly better pain reduction at 3 months (p = 0.02) and 6 months (p = 0.002) compared to control interventions.
Franke et al. (2000) – A randomised, sham-controlled study published in Rheumatology followed 60 patients with rheumatoid arthritis. After 6 months of follow-up, the radon group maintained significant improvements in both pain intensity (−16.9%, p = 0.04) and functional capacity (AIMS score, p = 0.01), while the sham group returned to baseline levels.
RAD-ON01 Observatory (2023) – Pain reduction was observed to last at least 30 weeks after treatment, with no radiation-related adverse events reported in any study.
The mechanisms are not fully understood, but the 2024 RAD-ON02 trial found no significant immune changes attributable specifically to radon, suggesting the pain relief is neurosensory rather than immunological. Other proposed mechanisms include autonomic nervous system modulation (shifting the body from sympathetic to parasympathetic dominance) and endorphin release triggered by the combination of heat and radiation.
Whether this holds up to further scrutiny remains to be seen. But the evidence from Jáchymov – and from the spas of Germany, Austria, and the Czech Republic – is compelling.
Two Camps
There are two camps. On one side, people who see radon as a radioactive gas that causes cancer – which is true at high doses. People have to have filters put in their houses to get rid of radon. On the other side, people who have done the science and say there is something in this.
There is also the pharmaceutical angle. They do not want to sell less paracetamol and ibuprofen. They do not want a treatment that may be just as effective.
Radon as Medical Treatment – Today
In the Czech Republic, radon baths are a bona fide, doctor-signed-off medical treatment. Through the equivalent of the NHS – more like medical insurance – you can get yourself signed off and receive up to 21 days at the Radium Palace or similar organisations. Full board, full lodgings, a series of radon baths, all tied in with full medical procedures. Doctors take readings, analysis, and check progress.
There are half a dozen places on this one street alone where you can get it done.
The Experience
I went to the Radium Palace for a radon bath. You go into a huge corridor with dozens of chairs and doors, into a mini changing room, and then into the bath itself. The rooms are not private – everyone is separated only by curtains. It is clinical, almost like going to the dentist.
They fill up the bath, you get in for 20 minutes, they set a timer, come back, wrap you in a towel and a sheet like a mummy, and tell you you have 10 minutes before you are off. No bubbles. No music. No nice smell. Just 20 minutes in radioactive water and then out.
How did I feel? A bit tingly. Especially my toes and my fingers. I do not know whether it was psychosomatic or whether it was an actual physical effect.
But the Geiger counter does not care about psychosomatic.
Back in my hotel room, I pointed the RadiaCode at the swimming trunks I had worn. The thing was registering between 1 and 1.5. I was surprised it was actually that high.
The dose from 20 minutes in one of those baths is roughly 0.2 to 0.5 millisieverts – the equivalent of a chest X-ray.
And it is not just a Geiger counter going off. I ran the spectrum analysis on the RadiaCode app and got clear radon peaks. Whilst the Geiger counter proves it is radioactive, the spectrum is the evidence. This was the real deal.
The Radon Boomerang
A 1920s cure-all. Debunked in the 1950s. Now back, and based on science.
But Jáchymov has more stories to tell. Before uranium, there was silver – it gave the world the dollar. There are rooms of radioactive, glowing rocks. There are glowing forests, spicy princess castles, and secret mine adits.
Then there is the dark side. Jáchymov became a forced-labour camp for dissidents and outcasts, and death is as much a part of this town as radioactivity.
Subscribe and stay tuned. We have only just started unravelling the mysteries of Jáchymov.
