Objective To compare the effect of glucosamine (Virtral-s) on the cartilage oligomeric matrix protein (COMP) secretion of chondrocytes and synoviocytes in vitro.Methods Chondrocytes and synoviocytes isolated from knee cartilage of osteoarthritic patients were cultured by phased enzymatic digestion.Sera containing Virtral-s of the experimental animals were obtained after orally administrated Virtral-s at the dosages that equal to human.Cells were cultured in the medium with Virtral-s containing sera.Super-natant COMP level was tested by enzyme-linked immunoabsorbent assays (ELISA).Results COMP conceu-tration of synoviocytes cultured in vitro was significantly higher than that of chondrocytes (P＜0.05).Virtral-s could significantly increase COMP secretion in cultured chondrocytes in vitro (P＜0.05),however,it had a weaker role on synoviocytes,ie,it could only mildly reduce COMP secretion of synoviocytes.Conclusion Glucosamine (Virtral-s)-containing serum can promote COMP secretion of chondrocytes in vitro,and it has no significant effect on synoviocytes in vitro.