Bacterial β-glucuronidases in human colon play an important role in cleaving glucuronide conjugates of dietary compounds, endobiotics and xenobiotics.They are encoded by two distinct groups of gene, gus and BG, and the isolates of human gut bacteria that carried only gus gene showed relatively higher activity.Activity of bacterial β-glucuronidases has been reported to change with some diseases.To date, little information is available on β-glucuronidase gene distribution in different individuals.This study aimed to characterize gus gene distribution in gut microbiota from 10 individuals (6 healthy volunteers and 4 ulcerative colitis (UC) patients) using degenerate PCR and denaturing gradient gel electrophoresis (DGGE).Degenerate primers were synthesized according to Marta Dabek2 and PCR products were cloned, sequenced and subjected to construction of clone library.