Cyanidin and its glycosides (Cy and Cyg) have been indicated as promising candidates as dietary compounds with a potential role in human health. They are the largest class of water-soluble compounds in plants, where they are responsible for the brilliant color (red, orange, blue) of fruits and flowers. As natural compounds of several foods such as vegetables, fruits and red wines, they are estimated to be widely ingested by humans. This paper, basing on the data previously reviewed in 2002, focuses on the findings regarding human and animal studies on Cy and Cyg absorption and metabolism, antioxidant activity and biological properties, with particular attention to anticarcinogenic activity, vasoprotective, anti-inflammatory, anti-obesity and anti-diabetes effects. It is concluded that although Cy and Cyg bioavailability is low, further investigations are necessary because some important metabolites may still not have been identified. Literature data on antioxidant activity and biological properties, however, widely confirm Cy and Cyg as dietary compounds with a potential beneficial role in human health.