Spa therapy includes all modalities/ treatments based on evidence that are administered in spas or sanatoriums. Balneotherapy, the immersion in mineral water, is the main balneological modality in spa therapy programs. Clinical trials performed in Europe, Turkey, and Israel have shown clinical benefits of spa therapy/ balneotherapy in several diseases mainly pertaining to rheumatic and musculoskeletal diseases and dermatological diseases as well. However, mechanisms by which balneotherapy may improve the clinical symptoms of patients have been less evaluated/ documented in the literature. Although the literature on mechanisms of action of balneotherapy has still been evolving and accumulating, some evidence from preliminary studies paves the way for generating a hypothesis that balneotherapy has an influence on physiological mechanisms, immune system, inflammation, and oxidative stress. Extrapolation of the evidence-based clinical practice and scientific experience of Europe, Turkey, and Israel to Central Asian spas and sanatoriums is although possible; future studies investigating clinical efficacy, safety profile, and possible mechanisms of action of balneotherapy of regional spas are needed to better understand the role of balneotherapy and whether it has any local differences.