The aim of our research was to analyze the antioxidant role and efficacy of thermal or salus per aquam (spa) therapy with chlorine-sulphur-bicarbonate mineral water. The study has been performed on 30 rats. The animals were randomized in three groups, each of them composed by ten animals, denominated A, B and C. The A group was the control group and was not subjected to any specific treatment (placebo); the B group has been treated with a standard cycle of hydropinics treatment with mineral water of Therme of Stabia in Castellammare (Naples, Italy) denominated STABIA; the C group was treated with a standard cycle of hydropinic treatment with mineral water of Therme of Stabia in Castellammare (Naples, Italy) denominated SULFUREA. After two weeks of treatment all the rats were sacrificed and blood was collected for the plasmatic determination of reactive oxygen species (ROS). The results demonstrated a significant (P < 0.05) reduction of ROS in B (374 Carr. U. +/-73) and C group (399 carr. U. +/-62) treated with mineral waters if compared with control group (571 + 69 Carr. U.). In conclusion this study suggests a possible antioxidant effect of chlorine-sulphur-bicarbonate spa hydropinic treatment with a consequent suitable intestinal physiology, with reduction of the functional and organic modifications that can lead to pathological disorders of the gastroenteric diseases in whose pathogenesis the oxidative stress can develop an important role.