Severe acute respiratory syndrome (SARS) is an acute respiratory tract infectious disease induced by SARS-CoV and mainly transmitted through the short-distance air droplets and close contact. Its main clinical characteristics is abrupt onset of the disease and the initial symptom is fever accompanied with systematic symptoms of headache, soreness and fatigue, and respiratory tract symptoms such as cough, chest dullness, and dyspnea. A few cases may progress to acute respiratory distress syndrome (ARDS). Due to its self-limiting feature, the prognosis is predominantly good but may be poor in severe cases, with mortality about 9.3 %. Some patients may develop such complications such as lung fibrosis and necrosis of the head of femur. On April 8, 2003, SARS was defined as a legal infectious disease by the Ministry of Heath of China.