Autohydrolyzed lignin was found to bind bile acids in vitro, an effect which was enhanced at low pH. Lignin with and without lactulose was fed to Golden Syrian hamsters to determine whether it could improve gallbladder bile composition by inducing small increases in bile acid excretion/ synthesis. Lignin-supplemented diets increased daily fecal lithocholate excretion in association with a significant reduction in biliary cholesterol saturation. Lignin and lactulose did not affect daily neutral steroid excretion, but the combination decreased cholesterol degradation in the intestine. Further experiments are required to assess the efficacy of autohydrolyzed lignin and lactulose in the prevention of cholesterol gallstone disease.