Zovirax Duo is a breakthrough cold sore treatment, clinically proven to help prevent the blister and speed healing. It's the only cold sore relief which contains an antiviral and anti-inflammatory agent. Talk to our pharmacists today on 1300 901 903. It contains aciclovir, an antiviral that fights the cold sore virus, and hydrocortisone, an anti-inflammatory agent. This unique dual action formula is clinically proven to help prevent the blister and speed healing.