Cholangiocarcinoma (CCA) is one of the major health problems that affects northeast Thailand. Liver fluke infection and hepatolithiasis have been identified as the etiological factors that influence the regional frequency of CCA. The liver fluke, Opisthorchis viverrini, is endemic to northeast Thailand and is closely related to the high incidence of bile duct cancer.1 The infection of O. viverrini occurs primarily in the liver, extrahepatic bile ducts, and gall bladder. The only potentially curative treatment for CCA is a surgery that is appropriate in less than 50% of cases.2 In patients with irresectable and metastatic CCA, chemotherapy has been used to control the disease and improve the patients’ survival rates. However, a relatively poor response rate of CCA to chemotherapy has been demonstrated in clinical studies.3 Therefore, a search for new and effective therapeutic agents is still needed. This has led to screening chemical constituents from Thai medicinal plants for cytotoxicity against cholangiocarcinoma cell lines.4−6