During the centuries, St. Casciano linked its name to the presence of hot springs. It is said that the first to discover these extraordinary waters was the great Etruscan king Porsenna, lucumo of Chiusi. Even though this information has not been currently confirmed by the archaeological studies, the exploitation of the baths by the Romans is certainly more than confirmed.

During the last years, throughout the St. Casciano countryside Roman tablets have been cropping out several times with carvings that substantiate the presence of the "Fonti Clusinii" used by the Roman nobles who easily reached the baths because of their closeness to the Cassia Way.
Researches, chronicles and treaties have repeatedly talked about the thermal activity that had its period of lowest decadence during the Middle Ages, also because of depopulation and the Barbarian invasions.
Nevertheless, even during those years, the inhabitants of the area preserved the historical memory of those places by keeping the toponym "ad-balneo" that still exists today, as indicated by the name of the municipality. This definition is reported in some documents of the X century.
It is possible, though, that the thermal activity started again around the XIII century. Among the famous people who attended St. Casciano there was the famous scholar Ugolino da Motecatini who dedicated a long part of his "Tractatus de Balneis", written in 1417, to this spa.
The St. Casciano baths became renowned since the XVI century, when nobles and clergymen from all over Europe crowded St. Casciano to take a cure. This period would have never been repeated. In effect, from the XIX century, a new kind of tourism started and it was based on thermal cures, modern facilities and luxury hotels, which the town of St. Casciano never succeeded to completely get used to.
There are four main baths in St. Casciano. The biggest bathing plant is the Bagno della Ficoncella near which Ferdinando de' Medici raised a porch to put into evidence his merits in the recovery of the thermal activity. Then, there is the Bagno Grande which originates from the most abundant spring; the Bagno Bossolo, with lukewarm waters for curing burns, and, lastly, the Doccia della Testa bath.
This is very well-known and is the most frequented bath by the local population. Its therapeutic properties stem from its strong hot water jets coming from above.