Hydrogen sulfide in thermal spring waters and its action on bacteria of human origin

► Hydrogen sulfide is a molecule dissolved in many thermal spring waters. ► Survival rate of three microbial species in waters with different titers of hydrogen sulfide has been investigated. ► Addition of hydrogen sulfide to waters has been performed to investigate the effect on bacteria growth. ► Results strongly support a bactericidal role of hydrogen sulfide in thermal spring waters used for recreational purposes.