The world's strongest sulfur brine used in therapy at the Physiotherapy Center comes from the “Malina” borehole in Solec-Zdrój. It is classified as a highly mineralized chloride-sodium (brine) sulfur, bromine, iodine, and boron water with the highest global content of active sulfur compounds.
The effect of balneotherapy depends on the concentration of active sulfur compounds in water. Using medicinal waters with high sulfur content (over 100 mg/1L) ensures the best therapeutic results in spa treatments. Like all stimulus therapies, it requires a series of treatments; effects last about a year after completion.
Overview of selected
sulfur waters in Poland
| Spring location | % mineralization | sulfur compounds in water |
| Swoszowice | 2.64% | 70.04 mg H2S/1L |
| Krzeszowice | 0.28% | 6.00 mg H2S/1L |
| Horyniec | 0.75% | 23.00 mg H2S/1L |
| Busko-Zdrój | 1.40% | 50.00 mg H2S/1L |
| Solec-Zdrój "Malina" | 3.10% | 830 mg H2S/1L |
