We investigated the intestinal absorption of the macromolecule human alpha-lactalbumin during and after an episode of acute gastroenteritis in children. Twenty children were studied in the acute phase and 17 excreted rotavirus. Eleven children were studied again 5-8 weeks later (convalescent phase). Human alpha-lactalbumin serum concentrations in the acute phase were similar but in the convalescent phase they were significantly (p less than 0.001) higher than those in the reference children. The serum concentrations were also higher in the convalescent than in the acute phase (p = 0.021). This study suggests that there is an increased absorption of proteins from the gut into the circulation 5-8 weeks after rotavirus gastroenteritis.