This systematic review, conducted in response to a request from the World Health Organization (WHO), evaluates the effectiveness of various treatments for severe acute respiratory syndrome (SARS) during the 2002-2003 outbreak. The review includes 54 studies on SARS-infected patients, 15 in vitro studies, and three acute respiratory distress syndrome (ARDS) studies. Key treatments assessed include ribavirin, lopinavir and ritonavir (LPV/r), corticosteroids, type I interferon (IFN), intravenous immunoglobulin (IVIG), and convalescent plasma. In vitro studies showed that ribavirin, lopinavir, and type I IFN inhibited SARS-CoV replication. However, in SARS patients, 26 out of 29 studies on ribavirin were inconclusive, and four showed possible harm. Seven studies on convalescent plasma or IVIG, three on type I IFN, and two on LPV/r were also inconclusive. For corticosteroids, 25 out of 29 studies were inconclusive, and four showed possible harm. The review concludes that it is not possible to determine whether these treatments benefited patients during the SARS outbreak, and some may have been harmful. The authors recommend that future clinical trials should be designed to validate standard protocols and monitor adverse effects to inform treatment strategies.This systematic review, conducted in response to a request from the World Health Organization (WHO), evaluates the effectiveness of various treatments for severe acute respiratory syndrome (SARS) during the 2002-2003 outbreak. The review includes 54 studies on SARS-infected patients, 15 in vitro studies, and three acute respiratory distress syndrome (ARDS) studies. Key treatments assessed include ribavirin, lopinavir and ritonavir (LPV/r), corticosteroids, type I interferon (IFN), intravenous immunoglobulin (IVIG), and convalescent plasma. In vitro studies showed that ribavirin, lopinavir, and type I IFN inhibited SARS-CoV replication. However, in SARS patients, 26 out of 29 studies on ribavirin were inconclusive, and four showed possible harm. Seven studies on convalescent plasma or IVIG, three on type I IFN, and two on LPV/r were also inconclusive. For corticosteroids, 25 out of 29 studies were inconclusive, and four showed possible harm. The review concludes that it is not possible to determine whether these treatments benefited patients during the SARS outbreak, and some may have been harmful. The authors recommend that future clinical trials should be designed to validate standard protocols and monitor adverse effects to inform treatment strategies.