Korner's Cold Sore Remedy is a natural health product used to help dry up and/or shrink cold sores, canker sores, and secretions. The active ingredient is a naturally sourced proprietary extract derived from the root of Geranium maculatum, commonly known as Cranesbill. This plant is traditionally valued for its especially powerful astringent properties, owing its effects to tannins and Gallic acid. In recent years, research has focused on its anti-viral properties.