For 3,000 years thermal water has gushed from the heart of the earth, inside a crater at a temperature of 37.5 ° C. The thermal water has traveled underground for 40 years from Monte Amiata, isolated by a 60 meter thick clayey to then emerge in the natural spring overlooked by the resort. Each liter of water contains 2,790 grams of dissolved mineral salts, as well as large quantities of gas, hydrogen sulfide and carbon dioxide.  Along with a continuous exchange of 500 liters per second and a complete replacement of the entire thermal system of Terme di Saturnia every 4 hours, the water is able to maintain its beneficial characteristics; specifically its rejuvenating qualities.

The thermal water of Terme di Saturnia is sulfurous (14 mg per liter of hydrogen sulfide), carbonic (462 cc per liter of free carbon dioxide), sulfate (contains sulfate ions in a prevalent quantity), and bicarbonate-alkaline-earthy (contains bicarbonate, calcium and magnesium ions in significant quantities). Due to its chemical composition, the water does not need any purifying treatment– it is the treatment itself; a strong natural medicine. Sulfur, in particular, has many benefits for the health of the body. It is a powerful bactericide and the key element of antioxidant molecules, useful in the fight against viruses and bacteria. It contains free radicals that promote longevity, and has a keratoplastic and keratolytic action that serve as a peeling agent, essential for stimulating cell regeneration.

The water of Saturnia, known to be "the largest natural open air aerosol in the world", can apply its benefits in numerous ways to boast therapeutic properties in various fields of medicine. It can be used in a solid state (in the form of sludge applied at a temperature of 45 ° C), a liquid state (also ideal for hydroponic treatments) and a gaseous state (for inhalation treatments). It prevents and treats diseases of the respiratory system as well as dermatological diseases, such as psoriasis, and ENT. It is also useful for joint rehabilitation therapies and indicated for arthrosis and osteoporosis.

Since the Roman legionaries and the Popes of the Middle Ages, the 'holy waters' of Saturnia have healed societies suffering from plagues and contagious diseases. It is reported that the Baths of Saturnia were used as shelters open for the reception of travelers and bathers and for the treatment of the most serious skin diseases, such as psoriasis.

Diving into the warm waters of the crater generates cenesthesia, or total well -being. 

Saturnia, has always been widely used in the treatment of skin diseases with its therapeutic virtues known since ancient times.

Its effectiveness and tolerability have been demonstrated at the most prestigious Italian University Centers. Tests of radical-scavenging activity were carried out on this alga and its extracts and were found to be antioxidants.