Phenolic compounds are the biggest group of phytochemicals, and many of them have been found in plant-based foods. Polyphenol-rich diets have been linked to many health beneits including cancer. The potential anti-carcinogenic mechanisms of action that have been so far identiied for phenolic compounds, as well as the feasibility reports occurred in vivo. In general terms, under the oxidative stress, polyphenols could act in those cellular mechanisms by participating in the modulation of the redox status and on multiple key elements in intracellular signal transduction pathways related to cell proliferation, diferentiation, apoptosis, inlammation, angiogenesis and metastasis. A protective role of polyphenols against carcinogenesis is supported by many studies carried out on animal models and diferent mechanisms of action have been proposed to explain such protective efects. Studies performed in animals have demonstrated that phenolic components can prevent and/or slow down the initiation-progression of diferent types of cancers. They act through the regulation of cell signal transduction and gene expression and exhibit either up or down regulation of genes controlling tumor development.