Whey protein is a mixture of globular proteins isolated from whey, the liquid material created as a by-product of cheese production. Some preclinical studies in rodents have suggested that whey protein may influence glutathione production and possess anti-inflammatory or anti-cancer properties; however, human data are lacking. The effects of whey protein on human health are of great interest and this protein mixture is being investigated as a way of reducing disease risk, or as a supplementary treatment for several diseases. Whey protein is commonly marketed and ingested as a dietary supplement, and various health claims have been attributed to it in the alternative medicine community. Although whey proteins are responsible for some milk allergies, the major allergens in milk are the caseins.