Thermes de Saint Gervais Mont-Blanc, Thermal bath complex in Le Fayet, France.

Thermes de Saint Gervais Mont-Blanc is a thermal bath complex with indoor and outdoor pools filled with naturally warm water from Mont Blanc springs. The water contains sulfur and trace elements used for therapeutic purposes.

In 1806 the notary Joseph-Marie Gontard had the hot spring in the Gorges du Bonnant analysed, bought the land and opened the first baths with four wooden tubs; in 1807 he added a storey and two turrets. Geneva doctor Matthey, appointed inspecting doctor in 1815, codified drinking, bathing, shower and steam treatments and linked the water to skin conditions. The 11 July 1892 rupture of a water pocket under the Tête Rousse glacier destroyed the establishment and killed more than 175 people; the rebuilt baths opened in 1894 about a kilometre downstream.

The name Saint-Gervais became attached to the water's reputation for skin conditions after Geneva doctor Matthey, appointed inspecting doctor in 1815, catalogued eczema, pityriasis alba and ulcers among the cases treated. His findings on the water's effect on the skin are still debated by scientists. Treatments later expanded to hydrotherapy: pulverisations, compresses and nitrogen, with Dr Deligny promoting spring-water care for children.

The baths stand at Le Fayet, about a kilometre downstream from the original 1806 site destroyed in 1892, in the Arve valley below the wooded slope. The building is reached from the hamlet centre; the entrance sign "THERMES" marks the main block with its balcony and dormer windows. Treatments follow the practice codified since 1815: drinking water, baths, showers and steam baths.

The 1894 building was erected about a kilometre downstream from the original baths, destroyed by the Tête Rousse glacier outburst of July 1892. Three Chamonix guides climbed to 3,310 m on 14 July 1892 and found that some 200,000 cubic metres of water had gathered under the ice.