The natural healing factor is the thermal spring, with a temperature of 32 to 34°C, which with its beneficial warmth soothes pain and enables easier movement.
In Laško mediates warm water on the surface of Triassic dolomite, which lies on impermeable Early Palaeozoic sandstone and clay schist.
The sources of the thermal water on the surface, under quaternary deposits respectively, are in close vicinity in a five hundred meter wide dolomite belt with impermeable sandstone to the north and pseudo-artery schist to the south.
By making wells it was discovered that the underground water appears in more horizons and that deep down there exists a connection between waters on the left and right banks of the river Savinja.
From the well in the vicinity of the Laško Health Spa we pump acrato thermal, alkaline calcium-magnesium, sodium hydrogen carbonate water with a temperature from 34,3°C to 39,4°C.