Effects of the protein fraction of Panax ginseng on chicken embryonic skeletal muscle cells cultured with a decfiient medium were studied. The protein fraction was further fractionated into four groups according to the molecular weight; larger than 10,000 dalton(fraction A), between 5,000 and 10,000 dalton(fraction B), between 1,000 and 5,000 dalton(fraction C), between 500 and 1,000 dalton(fraction D). According to the microscopic observation, all four protein fractions at the concentration of $10{sim}100{;}{mu}g/ml$ showed the tendency to stimulate the growth and differentiation of the muscle cells. The activity of acetylcholinesterase in muscle cells was significantly elevated by the protein fraction A at the concentration of $100{mu}{;}g/ml$. Protein fractions B,C and D significantly enhanced the synthesis of RNA in the muscle cells. The synthesis of DNA in muscle cells was significantly enhanced by protein fractions A,B and C.