ABSTRACT
The warming effect of alkaline saline springs is thought to be caused by the presence of Na<sub>2</sub>SO<sub>4</sub>·NaHCO<sub>3</sub>. To clarify the warming effect of alkaline saline springs, an experimental study was carried out using 5 adult rabbits for each 36-37°C bath every day for 20 minutes without anesthesia, on the assumption that cells in the skin tissue were activated to produce histamine by chemical stimulation. The chemical composition of each artificial salt bath was 4 times higher than normal. Skin histamine was measured by fluorescence analysis.<br>Single bathing in each artificial salt bath had no significant effect on the skin histamine contents. However, the skin histamine contents after a serial bathing in Na<sub>2</sub>SO<sub>4</sub>·NaHCO<sub>3</sub> (p<0.01) and CO<sub>2</sub> baths (p<0.05) for 3 weeks were significantly increased compared with that of tap water.<br>The small amount of histamine released as a chemical mediator may have caused the warming effect, as observed in type 1 allergic reaction.