The spread, patterns, and risk factors of alimentary diseases were examined in children residing in areas of petroleum-refining, petrochemical, and chemical industries. A total of 4816 children aged 3 to 14 years who lived in Ufa areas differing in the level and nature of ambient air pollution were examined. Those living in the poorer ecological areas (high total pollution and levels of chlorinated hydrocarbons, formaldehyde, and phenol) had more commonly gastroenterological diseases with prevailing hepatobiliary disorders in the pattern of diseases. The specific features of the diseases in these children are earlier onset, more frequent recurrences, more prolonged exacerbations involving other organs and systems than in those living in more favourable areas.