The serum lipid-bound sialic acid (S-LSA) levels of 77 functional constipation patients and 80 health subjects were measured with the thiobarbituric acid colouration method, with the results of 505.84±175.51 and 418.53±114.74μmol/L respectively. (P<0.001). The S-LSA levels of the hard stool group and the soft stool group were 547.61±180.06 and 436.71±168.24μmol/L respectively (P<0.01). The equation of linear regressions and cor-relation coefficients among the cource. the period of defecation of the patients and S-LSA levels were Y=298.59+24.48X. r=0.773. P<0.001 and Y=147.37+53.81X, r=0.792, P<0.001, respectively, suggesting abnormal metabolism of lipid-bound sialic acid in the functional constipation patients.