BACKGROUND: Colorectal cancer (CRC) is the third most common malignant tumor, and the fifth cause of cancer-related death in China, while chemotherapy is the primary strategy for CRC. Transient receptor potential (TRP) channels are non-selective cation channels while modulating the expression or activity of TRP channels results in the regulation of Ca OBJECTIVE: The study aims to investigate the effect of ISL on altering cytosol calcium in CRC cells and elucidate its potential molecular mechanism. METHODS: The study was conducted on 2 CRC cell lines HT29 and HCT116. Changes of cytosol calcium was indicated by live cell Ca RESULTS: ISL significantly increased cytosol calcium in HT29 and HCT116 cells. The ISL-induced increasing calcium ions were from both calcium influx and intracellular calcium release. ISL co-culture directly upregulated the expression of transient receptor potential vanilloid-1 (TRPV1) in colon cancer cells. Inhibition of TRPV1 by capsazepine (CapZ) abrogated the ISL-induced calcium influx and ISL-induced apoptosis in HT29 and HCT116 cells. CONCLUSIONS: This study illustrates, for the first time, that ISL increased cytosol calcium concentration and induced apoptosis via TRPV1 in colon cancer cells, giving a new understanding of the underlying mechanism of its anti-cancer ability and making it a potential regulator for TRPV1.