Herpesvirus replication is characterized by a cascade of coordinately regulated events. The inhibitory effect of peppermint oil was determined following addition at different times during viral infection. To identify the step at which replication might be inhibited, cells were infected with HSV after preincubation of the cells with peppermint oil, pretreatment of the virus with the essential oil prior to infection, addition of the essential oil during adsorption or after the adsorption period