entrance to the part of the cave reserved for speleotherapy. Teufelshöhle, Germany.
Speleotherapy in the Eisensteinstollen in Bad Grund, Harz, Germany.

Spelaeotherapy uses the special climatic conditions in caves and mines to cure various diseases, especially respiratory diseases.

Centuries ago, miners or cave visitors felt an improvement in health after returning from underground. These reports became legend until the 20th century, when some medical researchers tried to track down the effect. It turned out that many caves and mines have hardly any dust in the air due to the humidity of 100 %. The water condenses on the dust grains, they become heavy and sink to the ground, the air is dust-free. Another important fact is the high proportion of carbon dioxide (CO2) in the cave air. This gas is in principle non-toxic, we breathe it out after our bodies have oxidised the carbon for energy. The atmosphere has a very low proportion of carbon dioxide (0.03%), the proportion in cave air is five to ten times higher, but still very low. However, the relatively high proportion influences the autonomic nervous system and leads to deeper and more intense breathing.

So there were soon individual healing tunnels, cave therapy centres, and spa operations. Only in time was the umbrella term spelotherapy introduced to summarise the diverse treatment methods.

Speleotherapy is a holistic or alternative medical treatment. Like all such procedures, it struggles with recognition by mainstream medicine. It is accused of insufficient proof of effectiveness through scientific studies and of falsifying results through the placebo effect. Proponents of the therapy explain that the elimination of the stimuli gives the body the opportunity to heal itself. That asthma attacks put additional strain on the body is obvious, so stopping the attacks is undoubtedly a benefit. That the symptoms of the diseases are alleviated or completely eliminated while the patient is in the cave is undisputed. The point of contention, then, is whether a long-term cure can result. The Cochrane report cited below could not find significant results in a reliable way, despite a positive short-term effect on lung function.

At least it can be said that the therapy has no side effects. The therapy in the cave works completely without any medication. Pregnant women with asthma can use the therapy without harming the child. However, the gentle effect of the therapy requires a longer-term duration, i.e. several weeks.

The effectiveness of speleotherapy is not recognised in all countries of the world. In Eastern European countries, it has been used for many decades and the therapy is paid for by the public health system. Some countries, including Great Britain and the USA, on the other hand, do not see any medical benefit in this therapy because there is a lack of serious scientific research. In these countries, the therapy is sometimes advertised as wellness or disease symptom management. In Central European countries, especially in Germany, speleotherapy experienced a kind of gold rush in the 2000s. In Germany, the therapy is not approved by health insurance companies, so controlled clinical trials were initiated to test its effectiveness. A study conducted at three German speleotherapy sites in 2002 proved the medical benefits of the therapy in children. (See dissertation by Dr Lindacher).