The study of nonbacterial gastroenteritis came of age in the early 1970s after many fruitless years spent in the search for an etiological agent. Virological aspects of this syndrome were studied in the 1950s and 1960s, using cell culture techniques, with very little reward for much painstaking laboratory work. With the successful development of organ culture techniques for the study of viruses 1 a possible approach to the study of viral causes of gastroenteritis became available. Although initial aspirations were high that organ cultures derived from human fetal intestine might provide the means of detecting fastidious enteric viruses, only limited success was achieved. Replication of a number of conventional human fecal viruses, which could also be propagated in cell culture, occurred in these intestinal organ cultures, 2 - 4 but not the elusive agents of nonbacterial gastroenteritis. The discovery of these agents awaited the application of newer technology and alternative approaches to the problem.