Ethnopharmacological knowledge and physicochemical properties of hot springs in Bhutan

Balneotherapy, the therapeutic use of mineral and thermal waters, is an ancient practice with global significance. In Bhutan, the use of hot springs is deeply ingrained in culture and traditions as balneotherapy practices, enriched by extensive ethnopharmacological knowledge. Therefore, this study aims to document the socio-cultural and ethnopharmacological importance of Bhutanese hot springs, analyse their physicochemical characteristics, and correlate them with the perceived therapeutic benefits.

The study focused on three hot springs in the Gasa and Punakha districts. Qualitative data collection on ethnopharmacological knowledge included informal conversations, semi-structured interviews, oral narrations, and focus group discussions. Thematic analysis was applied to interpret the data. Physicochemical properties of the thermal waters were analysed following standard laboratory protocols. Piper and Stiff plots were used to determine the water type and ion concentration, respectively. Moreover, Spearman's correlation coefficient was used to assess the physicochemical relationships of the thermal water to the perceived health benefits.

The study found that people visit hot springs for spiritual connection, social bonding, and therapeutic benefits for musculoskeletal, dermatological, gastrointestinal, respiratory and cardiovascular conditions. The Piper diagram revealed that all hot springs exhibit a sodium-chloride (Na⁺-Cl⁻) hydro-chemical facies, suggesting a common geochemical origin. Stiff plot showed higher concentrations of ions in Gasa hot spring than other two sites. A moderate positive correlation was found between the concentrations of calcium, sodium, potassium, and magnesium, and the perceived health benefits for musculoskeletal and dermal conditions.

This study highlights the cultural, spiritual, and therapeutic importance of hot springs in Bhutan. The ethnopharmacological benefits, particularly for musculoskeletal and dermal conditions, is found to be linked to the physicochemical composition of the thermal waters. However, it calls for more research in terms of physicochemical analysis of thermal waters and clinical trials to scientifically validate these practices so they can be institutionalized as complementary and alternative treatments.