Bagni San Filippo is a small hilly thermal resort located in the province of Siena at the boundary between the chalky flat landscape of Valdorcia and the Monte Amiata rich in forests and sources. The place looks suggestive because of the white calcareous deposits formed by the water, where the village lies. These deposits form characteristic falls that face onto the Fosso Bianco. The legend ascribed the gushing of the prodigious water to the Florentine San Filippo Benizi, who lived here for a period of prayer and meditation in 1276. The baths were already attended for treatments in the Middle Age, but they achieved their greatest fame in the Renaissance, as witnessed by the quotation of the thermal baths in the Mandragola of Machiavelli and distinguished attendances of Pope Pius II Piccolomini, Lorenzo il Magnifico and Pandolfo Petrucci Lord of Siena. At the same time the studies on the water properties developed. They were recalled in the XVI century by the greatest experts of thermal baths like Ugolino da Montecatini, Gentile da Foligno and Andrea Bacci. New impulse received the baths during the Nineteenth and Twentieth century, when scientific studies and detailed analyses spread their therapeutic efficacy not only for rheumatic and arthritic diseases, but also for diseases of skin, respiratory tract and ear, nose and throat. At present, the water of San Filippo Thermal Baths is used in the establishment for bathing therapy, mud-baths, inhalation treatments and in the well-being center for aesthetic and relaxation treatments.