Since nutritional research has traditionally focused on macronutrients (proteins, lipids, sugars) and essential micronutrients (vitamins, minerals), food plants have long been assumed to contain few if any secondary metabolites apart from those revealed by our senses and responsible for their taste and flavour. Over the past few decades, evidence has, however, been mounting that food plants also contain a host of secondary metabolites which, though generally undetected by our senses, can nevertheless contribute to human well-being and play a role in the maintenance of health (Pisha and Pezzuto, 1994). Evidence for the dietary intake of biologically active small molecules can be traced to two distinct lines of research, namely the study of the detrimental effects of the inordinately large consumption of single food plants, and the recognition that food and medicines can interact, sometimes with dramatic consequences. Research in these areas has always been intense, and recent highlights are the identification of the configurationally unusual (17- side-chain) dammarane 1 as the immunosuppressive principle of Palmyra palm flour (Révész et al., 1999), and that of the furanocoumarin 2 (bergamottin) as the main cause of the ‘grapefruit effect’ which plagues the pharmacokinetics of several important drugs (He et al., 1998).