Plants are sessile organisms, and consequently cannot avoid exposure to stressful environmental conditions. Exposure to mild stress conditions can induce active acclimation responses, while more severe conditions cause metabolic disruptions. A common plant acclimation response to a variety of environmental stressors is the accumulation of antioxidants and secondary metabolites. For example, ultraviolet-B (UV-B) radiation impacts on the levels of a broad range of metabolites, including phenolic, terpenoid and alkaloid compounds. Our survey of the literature reveals that the levels of some of these metabolites increase following UV-B exposure, while those of others decrease, change transiently or are differently affected by low and high UV-doses. This includes several compounds that are pharmacologically active and/or nutritionally important. We conclude that the complex patterns of stress-induced changes in plant metabolites need to be studied in more detail to determine impacts on the nutritional and pharmacological characteristics of food products. Claims that UV-B acclimated plants have nutritional benefits are currently unproven. (c) 2008 Elsevier Ireland Ltd. All rights reserved.