In the national sanatorium "Sanyoso" we have treated many cases, who during and after the pulumonary or intra-thoracic operation, often showed impediments in the respiratory and circulatory organs-abnormal blood pressure ascension and pulmonary edema-, in which occasion we perceived that neither oxygen inhalation nor pressure reducing remedies nor any kind of medication proved effective before it worked wanderst o have the patient body lowered to 15°-20° on its operated side. In this connection close examinations have been carried through to investigate the abnormal blood pressure ascension and its counterplan, and the following results have been obtained from them: 1. The blood pressure was hightened by the positive changing of the intra-thoracic pressure or by chest opening (thoracotomy), which was found to be mostly connected with the decrease of oxygen content and the increase of carbonic acid gas content, more especially with former. 2. In this state of blood pressure ascension, it is considered that the cardiac output is less than normal owing to the congestion in the vena cava and the right auricle, caused by the decrease in the pulmonary circulation blood volume. 3. Under such a condition that the blood pressure schould be lowered by bleeding, the pressure change in the thorax sometimes gives such a rise to the blood pressure as if it were a normal one. Ⅰ, therefore, call it the "Abnormal Blood Pressure Ascension". 4. In case such as in 3 the blood pressure is regained to the pressure as originally was by lowering the body 15°-20°on its operated side. It serves to foresee dangers of every kind as well as clinical shocks. 5. In case that abnornal blood pressure is caused to rise by the intra-thoracic pressure the change of body posture lowered th 15°-20° on the side where the intra-thoracic pressure has been hightened, serves to improve the arterial blood gas as well as to lower the blood pressure.