Fruits and vegetables of the human diet contain many of the over 600 carotenoid pigments that have been identified in plants. Led by work with beta-carotene, researchers have constantly been learning more about the metabolism of these compounds in the human body. Research work is now expanding beyond beta-carotene in an effort to understand what happens to all the pigments found in the human diet. This discussion briefly looks at research results on the carotenoids found in human serum as well as the effects of supplementation. Recent confusing results from large intervention trials with beta-carotene and lung cancer incidence are emphasized in relation to supplementation doses and beta-carotene source (synthetic vs. natural). The summation of results emphasizes the importance of the broad spectrum of carotenoids in the diet and relates to supplementation products currently being designed for the marketplace.