Frankincense and lemongrass are the two essential oils with the largest bodies of research in this field. Research published in the May 2009 Journal of Chemico-Biological Interactions concluded "Our results indicate that the oil has a promising anti-cancer activity and causes loss in tum,or cell viability by activating the apoptotic process as identified by electron microscopy." For the latest research, go to pubmed.gov and search for "lemongrass" and "cancer".