OBJECTIVE: To investigate the effect of Aloe polysaccharide on proliferation and hyaluronic acid and hydroxyproline secretion of human fibroblasts in vitro. METHODS: The fibroblasts were treated with different doses of polysaccharide (0, 25, 50, 100, 200, 400 mg/L). Subsequently, cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cell cycle by flow cytometry, evaluation of the Aloe polysaccharide toxic effect by acridine orange-ethidium bromide staining, evaluation of the cell injury by lactate dehydrogenase (LDH) assay, and the collagen synthesis by (3)H-proline incorporation. In addition, hyaluronic acid and hydroxyproline levels in the supernatants of cultured fibroblasts were measured by enzyme-linked immunosorbent assay. RESULTS: The proliferation of fibroblasts was induced with polysaccharide in a dose-dependent manner, reaching its highest level on 5th day. Meanwhile, the percentage of cells at phase G(0)/G(1) was decreased, while that at phases G(2)/M and S was increased significantly in Aloe polysaccharide-treated groups as compared with those in the control group (P