Usnic acid (Usniacin) is a furandione found uniquely in lichen that is used widely in cosmetics, deodorants, toothpaste and medicinal creams as well as some herbal products. It exhibits antiviral, antiprotozoal, antiproliferative, anti-inflammatory and analgesic activity. Usnic acid inhibits breast tumor angiogenesis and growth by suppressing VEGFR2-mediated AKT and ERK1/2 signaling pathways.