Carthamin is a natural red colorant, which has been used worldwide for more than 4500 years. Moreover, it is the major component of Japanese “beni”, which is used for dyeing textiles, cosmetics, and as a food colorant, however, its biosynthetic pathway has long remained uncertain. In this issue, Waki et al. (on pp. 1528-1541) have identified the gene coding for carthamin synthase, the key enzyme of carthamin biosynthesis in safflower (Carthamus tinctorius L.) florets. Based on the elucidated properties of this enzymatic reaction, the molecular mechanisms underlying the red pigmentation process of safflower florets used for the traditional “beni” manufacturing process may now be explained. See also accompanying Commentary article by Suzuki (on pp. 1506-1508).