Phenol-Explorer is a comprehensive online database that provides detailed information on the polyphenol content in foods. Polyphenols, a major class of phytochemicals, are known for their antioxidant properties and potential health benefits, including the prevention of chronic diseases such as cardiovascular disease, certain cancers, and type 2 diabetes. The database includes over 37,000 original data points from 638 scientific articles, covering 502 polyphenols in 452 foods. The data were evaluated and aggregated to produce representative mean content values for each polyphenol. The web interface allows users to query the database to identify foods containing specific polyphenols or polyphenols present in specific foods. Each mean content value can be traced back to the original data and literature sources. Phenol-Explorer is a significant advancement in the field of food science and nutrition, providing valuable information for researchers, food manufacturers, and consumers. The database is accessible at http://www.phenol-explorer.eu.Phenol-Explorer is a comprehensive online database that provides detailed information on the polyphenol content in foods. Polyphenols, a major class of phytochemicals, are known for their antioxidant properties and potential health benefits, including the prevention of chronic diseases such as cardiovascular disease, certain cancers, and type 2 diabetes. The database includes over 37,000 original data points from 638 scientific articles, covering 502 polyphenols in 452 foods. The data were evaluated and aggregated to produce representative mean content values for each polyphenol. The web interface allows users to query the database to identify foods containing specific polyphenols or polyphenols present in specific foods. Each mean content value can be traced back to the original data and literature sources. Phenol-Explorer is a significant advancement in the field of food science and nutrition, providing valuable information for researchers, food manufacturers, and consumers. The database is accessible at http://www.phenol-explorer.eu.