Severe Acute Respiratory Syndrome (SARS) is the first major novel infectious disease to hit the international community in the 21st century. It originated in southern China in November 2002, reached Hong Kong in February 2003 and spread rapidly thereafter to 29 countries/regions on five continents. At the end of the epidemic, the global cumulative total was 8098 with 774 deaths. Seven Asian countries/regions were among the top ten on the list. Mainland China and Hong Kong, SAR, accounted for 87% of all cases and 84% of all deaths. Severe acute respiratory syndrome is caused by a novel coronavirus. It has alarmed the world with its infectivity and significant morbidity and mortality, its lack of a rapid, reliable diagnostic test and lack of effective specific treatment and vaccination. The adverse impact on travel and business around the world, particularly in Asia, has been enormous. Some lessons learnt from this epidemic included: (1) any outbreak of infectious disease can rapidly spread around the world by air travel; (2) early reporting of the outbreak to neighbouring countries/regions and the World Health Organization is essential to prevent international spread; and (3) infection control, tracing and quarantine of contacts are essential to control the epidemic. Many questions remain unanswered, including the origin and pathogenesis of the novel coronavirus, the natural history and the best specific treatment of the disease. The SARS-CoV has probably jumped from an animal host to humans. There is an urgent need to evaluate the human-animal habitat in southern China and to remove animal reservoirs if found.