AIM: Elevation of alanine aminotransferase (ALT) level iscommonly seen among patients suffering from severe acute respiratory syndrome (SARS). We report the progression and clinical significance of liver derangement in a large cohort of SARS patient.METHODS: Serial assay of serum ALT was followed in patients who fulfilled the WHO criteria of SARS. Those with elevated ALT were compared with those with normal liver functions for clinical outcome. Serology for hepatitis B virus (HBV) infection was checked. Adverse outcomes were defined as oxygen desaturation, need of intensive care unit (ICU) and mechanical ventilation and death.RESULTS: Two hundred and ninety-four patients wereincluded in this study. Seventy (24%) patients had elevatedserum ALT on admission and 204 (69%) patients hadelevated ALT during the subsequent course of illness. Using peek ALT ＞5xULN as a cut-off and after adjusting for potential confounding factors, the odds ratio of peek ALT ＞5x ULN for oxygen desaturation was 3.24 (95%CI 1.23-8.59, P = 0.018), ICU care was 3.70 (95%CT 1.38-9.89, P = 0.009), mechanical ventilation was 6.64 (95%CI 2.22-19.81, P = 0.001) and death was 7.34 (95%CI 2.28-24.89, P = 0.001). Ninety-three percent of the survived patients had ALT levels normalized or were on the improving trend during follow-up. Chronic hepatitis B was not associated with worse clinical outcomes. CONCLUSION: Reactive hepatitis is a common complication of SARS-coronavirus infection. Those patients with severehepatitis had worse clinical outcome.