Objective To examine the expression of PPAR-? in the biopsy of colonic mucosa of patients with ulcerative colitis(UC) and assess its relationship with the seriousness of disease .Methods The biopsy specimens were taken endoscopically from 31 patients with ulcerative colitis (UC) and from 12 IBS control separately. The expression of PPAR-? antigen in colonic mucosa was detected by immunohistochemisty(IHC) of the labeled-avidin-biotin method .The first antibody was mouse to human monoclonal IgG antibody against PPAR-?.Results The percentages of positive cells in the lesion of UC its juxta mucosa and control were 24.7%?1.4 9%,43.8%?2.03% and 70.2%?3.75%(P