Increased incidences of cancer caused by dysregulated gene expression or dysfunctional genes, in addition to the side effects of chemo- and radio-therapies, have led to studies featuring more natural treatments. Various natural compounds, also called cancer-preventive, and/or phytochemicals possessing significant anticancer properties, are now in demand as an alternative to traditional cancer treatments, although their low selectivity may limit their use. New approaches involving encapsulation, micelle formation, coating as nano- and micro- particles, and combined use of phytochemicals to increase their diffusion through different delivery systems with their anticancer properties against various types of cancer are proving very promising. Phytochemicals, their mode of action, current studies to accelerate their effectiveness, and future trends are summarized in this chapter.