Clinical studies of topical acyclovir therapy in recurrent HSV episodes are reviewed. Efficacy is maximised by early patient initiated treatment at the onset of prodromal symptoms. Acyclovir cream is clearly superior to acyclovir ointment in treating recurrent genital and labial herpes where the antiviral and clinical benefits are comparable with those produced by short duration oral acyclovir therapy. Acyclovir cream is well tolerated and adverse events remain uncommon whilst efficacy persists even after repeated use in successive recurrent episodes. Topical therapy does not influence the natural history of recurrent HSV infections. For patients with less frequent recurrent HSV episodes involving localised and accessible sites topical acyclovir cream may be preferred to the equally effective but more expensive oral acyclovir.