Of a series of ninety-six young male Syrian Golden hamsters, 13% developed lethargy, anorexia, diarrhoea and colocolic intussusception when their diet was changed from a basal laboratory-grade rodent chow to a nutritionally complete semi-purified diet. Histologically, the colon of the hamsters with intussusception had markedly reduced mucus production. Plasma levels of gastric inhibitory polypeptide (GIP) were reduced 80% (P< 0.01) but peptide tyrosine/tyrosine and enteroglucagon in plasma were increased 290 and 526 % respectively in hamsters with intussusception. Variations in dietary fatty acid composition had no effect but intussusception was not observed after changing the dietary carbohydrate from sucrose to starch.Colon: Cystic fibrosis: Intussusception: Peptide hormones: Hamster