The hot springs at Harkány unique in Europe bubble up from the ground from a depth of 50–70 metres, at an average temperature of 62 °C Its mineral content is more than 1000 miligrams per litre. The most valuable component from a medicinal point of view is a compound having bivalent sulphur, carbon sulphide (COS), which, as a gas, is in solution and under pressure in the water. When the water comes to the surface, the gas is released from under the pressure and immediately begins todecompose, it turns into hydrogen sulphide gas, which is responsible for the characteristic odour.

In a side-light, the precipitated tiny grains of elementary sulphur can be plainly observed in the ponds. Approximately 12 mg carbon sulphide can be found in 1 litre of water. By the way, this compound had not been known before, it was discovered here during the chemical analysis of the water in the 1860s. It is very actively absorbed both through the skin and via breathing: its absorption is 150 times as effective as that of tetravalent sulphuric compounds (sulphates).     

In our bodies, the bivalent sulphuric atoms are important components of the organic molecules making up the articular cartilage. 90 per cent of patients complaining of a locomotor disorder, suffer from degenerative spinal and articular conditions. First of all, the joints bearing the greatest load: the glassy cartilage in the hips, knees, and ankles get damaged. The mechanical overload (as, for example, in case of an overweight body) is manifest in increased clinical symptoms, such as swelling, pain, difficulty of locomotion. The sulphur getting into the system – which is demonstrably well metabolized – has an important role in the re-composition of the organic compounds making up the cartilage. That is the chemical effect of the medicinal water. Beyond that, the buoyancy in the water, the hydrostatic pressure – through which the weight of the body decreases and the load on the joints is also less – the hydrodynamic effect, and the thermal effect also have roles in the healing power.

But sufferers from chronic gynaecological inflammations also get healed here. According to earlier studies, 30 per cent of sterile woman treated here got later pregnant.