Four pure chemicals, ellagic acid (E), caffeic acid (C), luteolin (L) and punicic acid (P), all important components of the aqueous compartments or oily compartment of pomegranate fruit (Punica granatum), and each belonging to different representative chemical classes and showing known anticancer activities, were tested as potential inhibitors of in vitro invasion of human PC-3 prostate cancer cells in an assay employing Matrigel™ artificial membranes. All compounds significantly inhibited invasion when employed individually. When C, P, and L were equally combined at the same gross dosage (4 μ g/ml) as when the compounds were tested individually, a supradditive inhibition of invasion was observed, measured by the Kruskal-Wallis non-parametric test.