Inhibition of viral assembly (protease inhibitors) and of fusion of viral and target membranes (fusion inhibitors) are general approaches to antiviral treatment, not specific for HIV. Nonetheless, the agents that induce these phenomena are most often specific for a given virus or virus family. Drugs developed for HIV treatment were reevaluated for use against severe acute respiratory syndrome-coronavirus (SARS-CoV) during and after the epidemic in 2003, in view of the absence of any other available treatment. Of the protease and entry inhibitors approved for treating HIV-infected patients, none was effective against SARS-CoV, although in vitro activity against this virus was reported for the protease inhibitor lopinavir/ritonavir, in results that have not been confirmed in the most recent studies. The epidemiologic methods used to assess this drug's efficacy are not robust. Preliminary results for SARS treatment with protease and entry inhibitors, although at early stages of development, are promising.