Coronary circulation was measured in the anesthetized and nonanesthetized dogs by means of ultrasonic Doppler's radiotelemetric apparatus. The ultrasonic pick-up was placed on the upper third of the descending branch of the left coronary artery. Nonachlazine considerably increased the coronary circulation in the anesthetized and nonanesthetized dogs. However, the action of the preparation lasted 2 to 3 minutes only and depended on the changes in the cardiac activity. In difference from nonachlazine, oxphedrine increased the coronary circulation to a lesser degree, but for a much longer time (20min on the average). Taking into consideration a high efficacy of these preparations under clinical conditions a conclusion was drawn that an increase of the coronary circulation was not the principal way of action for reaching the antiangina effect in the patients with ischemic heart disease.