Phenolic compounds in foods originate front one of the main classes of secondary metabolites in plants. They are essential,for the growth and reproduction of plants, and are produced as a response for defending injured plants against pathogens. In recent years, there is a growing interest in phenolic compounds and their presumed role in the prevention of various degenerative diseases, such as cancer and cardiovascular diseases. The importance of antioxidant activities of phenolic compounds and their possible usage in processed foods as a natural antioxidant have reached a new high in recent years. The absorption and bioavailability of phenolics in humans are also controversial. Data on these aspects of phenolics are scarce and merely highlight the need for extensive investigations of the handling of phenolics by the gastrointestinal tract and their subsequent absorption and metabolism. In this article, absorption, metabolism, and the bioavailability of phenolic compounds are reviewed.