Patients with pain in the left side of the rib cage, the common causes are as follows: 1, coronary heart disease: coronary heart disease patients, due to insufficient blood supply to the heart muscle, will be manifested as pain in the left side of the rib cage that is angina pectoris. Coronary heart disease is the short form of coronary atherosclerotic heart disease, that is, responsible for giving the heart blood supply, oxygen supply of the coronary arteries, by the influence of atherosclerosis, serious narrowing, resulting in vascular occlusion. Patients with coronary heart disease, under the influence of emotional tension, excitement, anxiety, anger, shock, strenuous exercise and other triggers, myocardial oxygen consumption will increase significantly, but due to the existence of serious lesions in the coronary arteries, making the body unable to give the heart a timely and adequate supply of blood and oxygen, which causes insufficient blood supply to the myocardium, triggering angina pectoris, leading to the patient’s left side of the ribs within the pain; 2. Other diseases: such as left side of the ribs, costal chondritis, intercostal neuralgia, the patient’s left side of the ribs, the patient’s left side of the ribs and the heart. Other diseases: such as left rib costochondritis, intercostal neuralgia, patients can manifest as pain in the left side of the rib cage, and the pain lasts about 2 weeks or so. Therefore, if the patient has the above phenomenon, and can not be identified, need to go to the hospital in time, by the professional doctor for evaluation and judgment, if necessary, cardiography, in order to clarify the diagnosis.