Cucurbitacin B is a plant-derived triterpene that has the classic four-ring structure of mammalian steroids. Cucurbitacin B suppresses metastasis mediated by reactive oxygen species (ROS) via focal adhesion kinase (FAK) in breast cancer MDA-MB-231 cells. Cucurbitacin B induces inhibitory effects via CIP2A/PP2A/Akt pathway in glioblastoma multiforme. Cucurbitacin B acts a potential insect growth regulator by antagonizing 20-hydroxyecdysone activity.