Glycocholic acid is a glycine-conjugated form of the primary bile acid cholic acid and has roles in the emulsification of fats.^1,2 It reduces expression of the gene encoding the farnesoid X receptor (FXR) and increases expression of the genes encoding the bile acid receptors TGR5 and S1PR2 in SNU-245 cells when used at a concentration of 1.6 μmol/ml.³ Glycocholic acid (250 μM) increases the intracellular accumulation and cytotoxicity of epirubicin in Caco-2 cells, as well as decreases expression of the genes encoding multidrug resistance protein 1 (MDR1), MDR-associated protein 1 (MRP1), and MRP2 when used alone or in combination with epirubicin.⁴ It increases absorption of epirubicin into everted sacs of rat ileum and jejunum when used at a concentration of 250 μM. The bile acid composition ratio of glycocholic acid is elevated in bile of patients with cholangiocarcinoma compared with patients with pancreatic cancer or benign biliary diseases.³ Serum levels of glycocholic acid are elevated in patients with hepatocellular carcinoma compared with healthy individuals.²