The invention described herein encompasses methods and compositions of preventing or treating cancer comprising the administration of a combination of therapeutically effective amount of catechins, a group of polyphenols found in green tea, and Capsicum extracts. Compositions of catechins include but not limited to, epigallocatechin gallate (EGCg), epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC). The unique compositions of the invention contain various combinations of the catechins and Capsicum extracts, in combination with each other or other therapeutic agents and are used to treat primary and metastatic cancers in humans. The invention also encompasses the varying modes of administration of the therapeutic compounds, including a formulation which may be used as a therapeutic compound for the treatment of cancer or as a dietary supplement for the prevention of cancer.