Abstract Cholangiocarcinoma (CCA) is a very aggressive tumor. Te development of a new therapeutic drug for CCA is required. Tis study aims to evaluate the antitumor efect of ∆9 -tetrahydrocannabinol (THC), the major psychoactive component of marijuana (Cannabis sativa), and cannabinol (CBN), a minor, low-psychoactive cannabinoid, on CCA cells and xenograft mice. THC and CBN were isolated, and their identities were confrmed by comparing 1 H- and 13C-NMR spectra and mass spectra with a database. Cell proliferation, cell migration, and cell apoptosis assays were performed in HuCCT1 human CCA cells treated with THC or CBN. Te phosphorylation of signaling molecules in HuCCT1 cells was...