Ursolic acid has been shown to suppress colon cancer (Wang et al., 2013) and hepatocellular carcinoma (Liu et al., 2017) by inhibiting STAT3 signaling, whereas paeoniflorin exerted anti-diabetic effects (Li et al., 2018) and suppressed glioma cell growth (Nie et al., 2015) by targeting STAT3. Here, STAT3 is linked to central nervous system cancer.