Cancer is a complex, multifactorial disease with multiple variants, and has been studied for decades, and yet our knowledge of its prevention and cure remains limited, also better medications for the treatment of cancer are required. Flavanols are polyphenol phytochemicals, common secondary metabolites in plants, with a broad spectrum of biological activities, including anticancer activity. From the modulation of apoptosis and inhibition of cell proliferation, are important therapeutic agents against cancer; they are usually easily absorbed and have a much higher degree of tolerance and lower toxicity than conventional chemotherapeutic agents. Using in silico methods has optimized the search for new anticancer agents, allowing the identification, with less investment of time and resources, of new therapeutic targets or core targets, the processes involved in the mechanism of action, and the estimation of therapeutic efficacy-toxicity, among other characteristics. However, the application of in silico methods in studying flavanols and cancer is still limited. This chapter collects and summarizes scientific evidence on the application of flavanols in different types of cancer based on in silico studies and, in some cases, supported by in vitro methods providing a starting point for further research and development of new therapies based on flavanols.