cancer is the second leading cause of death in the world, and it was estimated to occupy the first place in the coming decades, especially in poor and developing countries. This pathology is characterized, among other factors, by the disordered growth of cells, through cell cycle alterations. (1) It is a disease of multiple origins, which can be caused by lifestyle, environmental factors, genetic infl uence, and the aging process of the organism. (2) Because it is a disease related to the cell cycle, processes that can damage cellular structures are factors favorable to neoplastic development. In this sense, fl avonoids-phytocomposites that have varied actions in plants, such as protection against ultra violet rays, protection against pathogenic organisms and antioxidant action-have been studied. Due to these properties, flavonoids have been evaluated for their therapeutic potential in the treatment of cancer, for having an antioxidant function, acting in the control of cell proliferation and in blocking neoplastic formation by mechanisms that regulate enzymes of the carcinogenic metabolic pathway. In addition, some of these compounds can inhibit the cyclooxygenase (COX) and lipoxygenase pathways, and important infl ammatory markers, showing an antiinfl ammatory property, (3) demonstrating their potential for maintaining cellular homeostasis, thus decreasing the chances of cell damage and the consequent neoplastic development. Studies demonstrate the therapeutic use of flavonoids to improve the prognosis, as well as prophylactic action regarding the development of breast cancer and thyroid cancer. (4,5)