Docosanol
"Less than 2 days ago I noticed a large herpes bump on my upper lip and immedietly my heart sank. I grabbed the Abreva I had and applied it right away but I figured it was to late. My first time trying it and in less than 48 hours of application the "bump" shrunk down and has practically dissapeared. No outbreak, no redness or scabbing stage. It's like I completly skipped the entire outbreak!:) Im gonna start hordeing Abreva. 5 star experience!"