# Balneotherapy with the Use of Radon-Sulphide Water: The Mechanisms of Therapeutic Effect
## 2 The Mechanism of the Therapeutic Effect of Radon-Sulphide Water
Sulphur is also involved in the synthesis of nucleic acids, it is part of the organic combinations of proteins and enzymes: oxydases, reductases, hydrolases, and transferases. It is particularly necessary in the synthesis of glutathione, which is indirectly involved in the processes of removing or neutralising ROS, as well as necessary for proper cellular metabolism. Sulphur is built into methionine and cysteine, and together with its oxidised form -S-S cystine, it is responsible for the formation of the active oxido-reduction centre of glutathione [19]. In their research, [PERSON] and [PERSON] confirmed the effect of sulphide and hydrogen sulphide water from Busko-Zdroj on the activity of the antioxidant system in patients with rheumatoid arthritis and degenerative spine and joint disease. They observed an increase in individual elements of the antioxidant defence of the organism [20; 21]. [PERSON]'s study also confirmed the effect of sulphide water on antioxidant defence indicators in patients with rheumatoid arthritis, showing an increase in the activity of individual elements of the antioxidant system [22]. Research carried out by [PERSON] on the use of artificial sulphide and hydrogen sulphide baths in the treatment of rheumatoid arthritis (RA) patients showed an improvement in their clinical condition by reducing pain, shortening the duration of morning stiffness, and decreasing swelling and the amount of anti-inflammatory medication taken. Laboratory tests showed a significant reduction in ESR (erythrocyte sedimentation rate), CRP (C-reactive protein) and \(\alpha_{2}\)globulin levels, Waller-Rose reaction titer, as well as the increased haemoglobin value, whose low level is indicative of rheumatoid arthritis [23]. Sulphide waters have keratolytic and keratoplastic effects; therefore, they are used in the treatment of dermatological diseases, including psoriasis. Especially useful in the therapy is the antipruritic effect due to blocking the release of inflammatory mediators [24]. Sulphur has been found to exhibit antifungal and antibacterial effects by reacting with free radicals in the deeper layers of the epidermis [25]. Sulphur, remaining on the skin surface, reacts with urea, leading to the formation of ammonium sulphide, which also has antiseptic properties [26]. In addition, by binding tissue oxygen, it slows down metabolic processes and decreases the mitotic activity of cells [27]. The presence of radon in the therapeutic water seems to be no less important. Radon waters are specific waters containing small amounts of the unstable radioactive element of radon and its decay products. Such waters are used in medicine, provided that the radon content in the water exceeds 74 Bq/L (2 nCi/L) and they meet the operational and hygienic requirements. Radon is commonly found in trace amounts in spring and river waters, but for medicinal purposes, it is obtained from natural outflows and boreholes. Radon is a chemical element formed in the radioactive decay of uranium and thorium. It occurs as a colourless and odourless noble gas that dissolves well in water, especially in poorly mineralised or acidified water. Radon exists in the form of many isotopes, the precursor of which is radon-222, which is formed directly from radium-226 through alpha decay. The emitted alpha particles have low penetrating power but high ionising power. The half-life is 3.8 days. Radon in high doses has a negative impact on health, and its harmful effects include the damage of enzymes and nucleic acids, which leads to the formation of neoplasms. Therefore, this should be especially taken into account while using radon as a medicinal material. The basis for the rationality of the therapeutic effect of radon waters is the hypothesis of so-called radiation hormesis. This theory was developed in the 1940s for the needs of pharmacology and toxicology. It states that small doses of ionising radiation activate life processes.