The third condition, sensitizing in multidrug resistance, according to Dehelean et al. [13], could be supported by usnic acid’s powerful effect-enhancing and toxicity-reducing in ascitic tumor-bearing mice treated with bleomycin [114]; usnic acid inhibits angiogenesis in vascular endothelial growth factor (VEGF) model and chick embryo [115]. This evidence concerns the gene VEGFA and neoplasm.