Effects of a single exposure to toluene at a concentration of 1000 for 4 h on rats' systolic blood pressure were investigated. 9 rats were used in each group (control and exposed groups). The basic blood pressure of the exposed group was significantly lower than that of the control group. The movement of systolic blood pressure due to impulse noise exposure was significantly smaller in the exposed group than in the control group. Toluene exposure at concentration of 1000 ppm for 4 h produced narcotic and inhibitory actions in the diencephalohypophysial and the adrenal gland system in rats.