If the left rib cage below the paroxysmal pain, the common clinical reasons are as follows: 1, coronary heart disease: if the myocardial blood supply is insufficient, may induce angina pectoris, and the left rib cage below the paroxysmal pain may belong to angina pectoris attack. Coronary heart disease is the short form of coronary atherosclerotic heart disease, is responsible for giving the heart blood supply, oxygen supply more important blood vessels coronary arteries, affected by atherosclerosis, resulting in coronary arteries serious narrowing or even cause occlusion. A significant increase in myocardial oxygen consumption can occur when patients with coronary artery disease are emotionally stressed, agitated, anxious, angry or frightened, and during strenuous exercise. Due to the existence of serious lesions in the coronary arteries, blood supply and oxygen supply can not be timely and adequate supply, it will cause myocardial blood supply is insufficient, induced angina attack; 2, left subcostal skin lesions: such as skin injuries, infections, such as herpes zoster, manifested in the left side of the subcostal paroxysmal pain; 3, other diseases: the left rib below the costal chondromalacia, intercostal neuralgia, can also lead to the left subcostal paroxysmal pain. If the patient can not identify the cause, you need to go to the hospital at the first time, by the professional doctor for evaluation and judgment.