Ingenol is an extremely weak PKC (protein kinase C) activator, with potent anticancer activity. Ingenol derivatives have received constant and multidisciplinary attention on account of their pleiotropic pattern of biological activity. This includes activation of PKC (protein kinase C), tumor-promotion, anticancer, and anti-HIV properties, and the possibility of dissecting co-cancerogenic and clinically useful activities has been demonstrated. Certain ingenol esters show powerful anticancer activity, and a structure-activity relationship model to discriminate between their apoptotic and non-apoptotic properties has been developed.