The present invention pertains generally to the field of therapy, and more specifically to the field of therapy for herpes simplex and herpes zoster, and more particularly, to methods of reducing the rate of relapse, delaying relapse, and/or preventing relapse of herpes labialis (cold sores on the lips), herpes genitalis (genital herpes), and herpes zoster (shingles, zona), by topical administration of polyethylene glycol (PEG), or a composition comprising PEG.