Immunoglobulin Y (IgY), an antibody present in birds, reptiles, and amphibians, is actively transported from the serum to egg yolks, where it is stored in large quantities. The use of chicken polyclonal IgY instead of mammalian IgG antibodies for biomedical applications has ethical and economic advantages, such as the lack of a need for animal bleeding because the antibodies are extracted from eggs after hen immunization and the low cost of the production and purification methods. This article reviews the latest IgY applications in diagnostic virology and the therapeutic use of IgY in viral gastroenteritis.