The article provides a detailed overview of the lung pathology associated with severe acute respiratory syndrome (SARS) in six patients who died from the disease. The study, conducted in Hong Kong during March 2003, included post-mortem tissue samples and an open lung biopsy from one patient. Key findings include diffuse alveolar damage, bronchial epithelial denudation, loss of cilia, and squamous metaplasia. Four patients showed giant-cell infiltrates with increased macrophages in the alveoli and interstitium, and two patients had haemophagocytosis. Electron microscopy revealed viral particles in the cytoplasm of epithelial cells corresponding to coronavirus. The authors suggest that cytokine dysregulation may contribute to the severity of the disease, and propose that the case definition of SARS should acknowledge the range of lung pathology associated with the disease. The study also highlights the importance of antiviral therapy and the potential for secondary infections in SARS patients.The article provides a detailed overview of the lung pathology associated with severe acute respiratory syndrome (SARS) in six patients who died from the disease. The study, conducted in Hong Kong during March 2003, included post-mortem tissue samples and an open lung biopsy from one patient. Key findings include diffuse alveolar damage, bronchial epithelial denudation, loss of cilia, and squamous metaplasia. Four patients showed giant-cell infiltrates with increased macrophages in the alveoli and interstitium, and two patients had haemophagocytosis. Electron microscopy revealed viral particles in the cytoplasm of epithelial cells corresponding to coronavirus. The authors suggest that cytokine dysregulation may contribute to the severity of the disease, and propose that the case definition of SARS should acknowledge the range of lung pathology associated with the disease. The study also highlights the importance of antiviral therapy and the potential for secondary infections in SARS patients.