Cholangiocarcinoma (CCA) is a major cause of cancer deaths in northeast Thailand. It is aggressive, highly metastatic, and responds poorly to traditional chemotherapy. We demonstrated the potential for Cepharanthine (CEP), a biscoclaurine alkaloid extracted from Stephania cepharantha, to treat CCA. CEP significantly inhibited growth of human CCA cell lines in a dose- and time-dependent manner, regardless of the histologic type of tumor origin. Increasing cell apoptosis via caspase-3 and capase-9 activation was demonstrated in CEP-treated cells. We found that CEP controlled the growth of CCA cells through nuclear factor-kappa B (NF-kappaB) inactivation by inhibiting nuclear translocation. CEP treatment effectively reduced tumor size in CCA-inoculated mice without serious side effects. CEP also increased cell apoptosis in primary histocultures of CCA patients' tissues; this was demonstrated by immunohistochemistry using TUNEL staining. Our results suggest that CEP possesses therapeutic potential against human CCA.