Perillyl alcohol has antitumor activity against rat mammary and liver cancer. Here, we report the chemotherapeutic effects of perillyl alcohol on pancreatic cancer. Perillyl alcohol reduced the growth of hamster pancreatic tumors to less than half that of controls (P < 0.025). Moreover, 16% of perillyl alcohol-treated pancreatic tumors completely regressed whereas no control tumors regressed (P < 0.05). Perillyl alcohol induced contact inhibition in cultured human pancreatic carcinoma cells and inhibited their anchorage-independent growth (P < 0.001). Thus, perillyl alcohol has antitumor activity against pancreatic carcinomas at non-toxic doses, and may be an effective chemotherapeutic agent for human pancreatic cancer.