Components of the plants viz. Artemisia vulgaris, Cichorium intybus, Smilax glabra, Solanum nigrum and Swertia chirayta have been used in traditional folk medicine to treat various human ailments; however, the anticancer properties have not been elucidated. We evaluated the anticancer properties of aqueous extracts of these plants against various human cancer cell lines. Exposure of aqueous extract of Solanum nigrum and Artemisia vulgaris exerted an inhibitory effect on cell growth and colony formation of the prostate, breast and colorectal cells. Other plant extracts exhibited a modest inhibition in cell proliferation for all three cell lines. These results were consistent with induction of apoptosis in cancer cells as measured by internucleosomal DNA fragmentation, caspase-3 activation and poly(ADP)ribose polymerase cleavage. Based on the in vitro data, it is suggested that consumption of the components of these plants or ingestion of extract as tea may impart anticancer effects especially in the colon, breast and the prostate.