Bioassay-guided fractionation of an ethanol extract of Smilax china led to the isolation of nine phenylpropanoids including six new compounds, smilasides A-F (1-6), and three known phenylpropanoids, smiglaside E, heloniosides B, and 2',6'-diacetyl-3,6-diferuloylsucrose. Structural elucidation of isolates 1-6 was based on spectroscopic data analysis. These new phenylpropanoids were evaluated against several human tumor cell lines.