The purpose of this study was to assess the vascular changes after thermophysical therapies using ice pack and ultrasound, investgate the mechanism of peripheral vasodilation by sympathetic nerve, and to observe the effects of the ergotamine to the thermophysical therapy. The author had used 16 healthy rabbits which were divided into 2 groups : with and without administration of ergotamine. Experimental animals were sacrificed 5, 10, 20 minutes after experiment, and were examined with gross and stereoscope of resin casting blood vessel models. The results were as follows : 1. Vasodilation was not remarkably found in the group with administration of egrotamine after thermophysical therapy. 2. Vasodilation was remarkably found in the group without administration of ergotamine after thermophysical therapy. 3. Vasodilation was increased in the group without administration of ergotamine, but not remarkably found in the group with administration of ergotamine in lapse of time 4. Thermophysical therapy was most effective to arterioles. Our data suggest that the dilation of peripheral blood vessels from thermophysical therapy was controlled by sympathetic nerve, because the blood vessels did not changed after administration of ergotamines which was a sympathetic nerve blocker.