The Terme Sillene spa water spring is on a hill where the ancient Etruscans celebrated their rites. The temperature at the spring is 38.5°C. Acqua Sillene is used for carbo-gaseous balneotherapy and in preparing thermal mud.
Acqua Sillene water contains considerable amounts of free carbon dioxide.
It is used in balneotherapy, supplementing hydropinic treatment and also serving as a basis for mud baths for the hepatic region. It is also used in carbo-gaseous balneotherapy for vascular diseases and in mud-balneotherapeutic treatment of arthrorheumatic diseases.