For Rh2, 20(S)-Rh2 reduced the viability of human colorectal cancer cells by inhibiting the interleukin-6 (IL-6)-induced activation of signal transducer and transcriptional activator 3 (STAT3) pathway and the expression of matrix metalloproteinases (MMPs), with such pharmacological activities much stronger than that of 20(R)-Rh2 (ref. 17). Here, STAT3 is linked to colorectal cancer.