The purification of cell growth stimulation peptide from human placental chorionic tissue that controls the division of a nomal human skin fibroblast (NLF) and several human cell lines maintained in tissue culture is reported. This cell growth stimulation peptide is about 15kDa by polyacrylamide gel electrophoresis and gel chromatography. The yield of cell growth stimulation peptide is 1.2mg per 100g of human placental chorionic tissue. Growth stimulating activity of DNA synthesis in NLF cells at concentration of 0.5μg/ml is equal to activity of 10% FBS
