Chinese herb Radix sophorae tonkinensis extract oxymatrine shows anticancer effects. This study evaluated the role of oxymatrine in colorectal cancer (CRC) and the underlying molecular events in vitro and in vivo. CRC cells were treated with different doses of oxymatrine to assess cell viability, reactive oxygen species production, gene expression, and gene alterations. Meanwhile, mouse xenograft and liver metastasis models were used to assess the effects of oxymatrine using histology examination, transmission electron microscopy, and Western blot, respectively. Our results showed that oxymatrine treatment triggered CRC cell mitophagy to inhibit CRC cell growth, migration, invasion, and metastasis in vitro and in vivo. At the gene level, oxymatrine inhibited LRPPRC to promote Parkin translocation into the mitochondria and reduce the mitophagy-activated NLRP3 inflammasome. Thus, oxymatrine had an anticancer activity through LRPPRC inhibition, mitophagy induction, and NLRP3 inflammasome suppression in the CRC cell xenograft and liver metastasis models. In conclusion, the study demonstrates the oxymatrine anti- CRC activity through its unique role in regulating CRC cell mitophagy and NLRP3 inflammasome levels in vitro and in vivo. © 2023 John Wiley & Sons Ltd.