The thermal baths in Gradačac erupt on a small hill, in the northern part of the town of Gradačac, between Lakes Hazna and Vidar. According to research, the thermal baths are formed at the contact of Triassic limestones, conglomerates and sandstones at the intersection of two faults. (Sarajlić, 2006). The most successful research of this water was carried out in 1979, when new spring capacities and mineral mud were discovered. Water analysis was performed at the Mining and Geological Institute and the Department of Physical Medicine and Rehabilitation, Faculty of Medicine, University of Zagreb, where the medicinal properties were determined. According to its physical properties, the water temperature is 29.5 ̊C, which is why it is considered a hypothermal mineral water. The water flow is 50 l / sec and the pH value is 7.1 (alkaline). According to its chemical properties, it contains the most cations, sodium and calcium, and anions, hydrocarbons and sulphates, which is why it is included in sodium, calcium, bicarbonate, sulphate weakly muriatic waters, with a mineralization of 889.49 mg / l and some free carbon dioxide. from 56 to 64 mg / l. Terma has low radio activity (0.397 millimicro rent), which means it cannot be classified as radio, active water. (Ilidža Spa Archive, Gradačac, 2012).