For patients with myocardial ischemia, if there is transient myocardial ischemia within a short period of time, or insufficient myocardial blood supply due to various factors of shock, the color of the lips and mouth are white, pale or yellowish-white at this time, and severe chronic myocardial ischemia. If the patient has unstable angina pectoris with coronary artery disease, or malignant arrhythmia or heart failure, the color of the patient’s mouth and lips at this time usually appears purple or purple liver color, which is due to the lack of oxygen caused by long-term insufficient myocardial blood supply, at this time there will be a decrease in arterial oxygen saturation, low partial pressure of oxygen and high partial pressure of carbon dioxide, and the mouth and lips usually have purple or even dirty black, if the patient has the above If a patient has the above-mentioned lip color, he or she must go to the hospital quickly to get a systematic examination to identify the original cause of myocardial ischemia and to treat it actively.