The epidemic of severe acute respiratory syndrome (SARS) has now been brought under control and entered the so-called post-SARS stage, with only a very few new cases reported daily throughout China. As an infectious disease spreading through the respiratory tract, SARS is featured by the inconsistency between its clinical representations, physical signs of the lungs and chest imaging findings. It has been shown that atypical pneumonia (AP), with similar clinical features to SARS, has been identified in Guangzhou, China, long before the prevalence of SARS, a fact that urges further understanding of SARS in regard to its incidence and variable clinical courses, for its differential diagnosis with such diseases as AP, influenza-related pneumonia, pulmonary tuberculosis, fungal and cytomegalovirus pneumonia. Information sharing among the medical institutes and training of the first-line medical staff for their better understanding and awareness of SARS and AP is crucial in the clinical practice, to insure timely case identification and avoid "oversensitive" diagnosis. Consultation of particular cases involving experts from multiple medical science fields should be encouraged, which is also an effective measure against newly emerged infectious diseases.