We report the case of an 84-year-old woman with advanced biliary tract cancer and accompanying colonic invasion and hepatic metastasis, who was successfully treated with single-agent gemcitabine chemotherapy in combination with juzentaihoto (a traditional Japanese herbal medicine). Response to this combination chemo therapy was extremely good, and the patient's tumors disappeared. There have been no reports like our case until today. These findings suggest that combined treatment with juzentaihoto and gemcitabine is effective not only for reducing tumor size, decreasing the side effects of chemotherapy, and maintaining general condition but also for mediating immune antitumor activity.