The present experiments were undertaken to elucidate the effect of serial bathing on plasma metabolites of rats. The rat took a bath for 10 minutes, 34℃ and 40℃ in temperature, in a city water once daily for two or four weeks. After serial bathing, the body weight and the
catecholamines, free fatty acid (FFA) and glucose contents in plasma were measured. The results are as follows: 1) The body weight showed a marked decrease after four weeks-serial bathing compared with that of the non-treated rats. 2) After two weeks-serial bathing, the noradrenaline (NA) content decreased slightly, but the adrenaline (A) content increased slightly compared with those in controls. After four weeks-serial bathing, no changes were observed in NA and A contents. 3) Plasma FFA content tended to increase by serial bathing compared with that in controls. 4) Although plasma glucose content tended to increase after two weeks-serial bathing, no change was observed after four weeks-serial bathing compared with that in corresponding controls.