Zovirax Cold Sore Cream 2gZovirax Cold Sore Cream contains aciclovir, an anti viral, which penetrates deep into the skin to fight the virus which causes cold sores. Zovirax is effective at both the tingle and blister stage, and shortens the duration of pain. Zovirax is clinically proven to help heal cold sores in as little as 3 days*. Use five times a day at approximately four hourly intervals for at least four days. Zovirax Cold Sore Cream helps you get your healthy lips