Plant foods are not only a main source of nutrients, but they are also rich in physiologically bioactive bionutrients or phytochemicals. Consumption of fruit and vegetables is associated with a decreased risk of pathological status, including cancer. Reactive oxygen species play a key role in the genesis and development of cancer. Therefore, antioxidant functions of phytonutrients have been thoroughly investigated in the last years in relation to their crucial effect in the pathophysiology associated with neoplasia. This review discusses current knowledge on phytochemicals in relation to their potential as chemopreventive and/or chemotherapeutic molecule against human cancers. Finally, we will outline the use of bioactive phytochemicals on synergistic actions involved in the prevention and treatment of cancer as well as its future prospects.