The Dendrobrium species have been commonly used in traditional Chinese medicine as a tonic to nourish the stomach, replenish body fluid, and reduce fever. However, their application as possible therapeutic agents for the treatment of cancers has not been examined. In this study, we want to examine the efficacy of using moscatilin, a natural antiplatelet agent extracted from the stems of Dendrobrium loddigesii, as an anticancer agent. Our results have shown that moscatilin exerts potent cytotoxic effect against cancer cell lines derived from different tissue origins, including those from the placenta, stomach, and lung, but not those from the liver. In addition, we have found that the mechanism of action of moscatilin may be related to its ability to induce a G2 phase arrest in responsive cells. However, unlike some G2 arresting agents, moscatilin has no detectable inhibitory effect on cyclin B-cdc-2 kinase activity. Thus, the precise nature of its cytotoxic mechanism remains to be determined. Our results in this study imply that moscatilin is potentially efficacious for chemoprevention and/or chemotherapy against some types of cancer.