Sixty-two sera from children under investigation for gastrointestinal disease were tested for IgA, IgG and IgM antibodies to gliadin by two different methods: an immunofluorescent (IF) test, and a mixed reverse (solid-phase) passive antiglobulin haemadsorption (MRSPAH) test. There was good agreement between the tests. Both tests detected gliadin antibodies of IgG and IgA class in sera from children with active coeliac disease, which tended to disappear when a strict gluten-free diet was instituted. Serum antibodies to gliadin of IgA class were associated with severe small intestinal villous atrophy and were found almost exclusively in coeliac disease. Gliadin antibodies of IgG class were less disease-specific and were occasionally detected in sera from children with gastrointestinal disease other than coeliac disease--notably in sera from children with transient gluten intolerance.