Cancer has been known as one of the genetic disorder and also as second cause for death in developed countries and/or even in developing countries. It has been estimated to be 26 million new cases of cancer and 17 million cancer death yearly. Some phytochemicals have been known to have anticancer activity and on the other hand modern medicine lacks effective drugs against certain types of cancers. Flavonoids are placed in the nucleus of mesophyll cells and inside centers of reactive oxygen species group. Alkaloids are known class of ring compounds nitrogen having organic compounds which have a broad range of anticancer properties. In this review article, we have described some phytochemicals and also possible mechanisms for prevention of cancer.