Equine anti-severe acute respiratory syndrome-associated coronavirus F(ab')(2) has been verified to protect mice from infection with severe acute respiratory syndrome-associated coronavirus (SARS-CoV). However, before potential clinical application, the antibody needs to be tested in as many animal models as possible to ensure its safety and efficiency. In this study, after verification by various methods that the golden Syrian hamster constitutes a model susceptible to SARS-CoV infection, we confirmed that the antibody could protect animals completely from SARS-CoV infection in the preventive setting. More importantly, the antibody could reduce viral titers or copies by approximately 10(3)- to 10(4)-fold in animal lung after virus exposure, compared with negative control. These data provide further evidence to warrant clinical studies of this antibody in the treatment and prevention of SARS.