The role of gliadin antibodies in coeliac disease is unknown. We have investigated this by maintaining jejunal biopsies from control subjects, treated and untreated coeliac patients in organ culture for 24 h. The tissue culture supernatants were assayed by enzyme-linked immunosorbent assay (ELISA) for total IgG, IgM and IgA, anti-gliadin and casein antibodies. Jejunal biopsies from untreated coeliac patients secreted more total IgM and IgA but not IgG, than biopsies from control subjects: values for treated coeliac patients were similar to those from control subjects. There was increased secretion of IgG and IgM gliadin antibody, but not casein antibody, by jejunal biopsies from untreated coeliac patients compared with those from control subjects.