The authors continuously observed the effect of Chuanxiongqin on the microcirculation of hamster cheek pouch by use of the Dual-Window Television Automatic Estimating System. It was seen that the caliber of arterioles, the microcirculatory velocity, and blood flow all decreased after local application of noradrenaline and all increased and returned to normal 1 to 30 min after local administration of Chuanxiongqin. Microcirculatory perfusion, however, could not be improved by normal saline or Iluangqi. The effect of Chuanxiongqin on the pulmonary capillary permeability was also investigated in rats. Pulmonary edema was induced in rats by adrenaline administration. Evans blue was injected intravenously and the amount of Evans blue in broncho-alveolar lavage fluid was estimated. It was found that Evans blue was increased in broncho-alveolar fluid of rats with pulmonary edema, and this increase could be lessened by Chuanxiongqin.