The mineral springs of Eger located at the southern foot of the Bükk mountains rise from the karst waters of the range. A favourable effect of the mineral springs of Eger on various kinds of illnesses, and especially on rheumatic diseases, was already know in the Turkish epoch (15th - 16th centuries). The curative power of these waters can first off all be explained by their slight radioactivity and by a prosperous effect of various trace elements contained in them on the vital functions of the organism. On the basis of complete analyses the medicinal waters of Eger may be divided into four groups.
Apart from the above mentioned elements the medicinal waters of Eger contain 51 kinds of trace elements; among them the most valuable are those that are neccessary for maintaining life, influence functioning of the cells and processes of catalyzing. They are also indispensable for functioning of the enzyme system.