Three new compounds, 2-hydroxy-5-butoxyphenylacetic acid, 2-fl-D-glucopyranosyloxy-5-butoxyphenylacetic acid, and entadamide A-fl-D-glucopyranoside, in addition to the new natural product 2,5-dihydroxyphenylacetic acid methyl ester, have been isolated and characterized from seeds of Entada phaseoloides collected in Indonesia. None of these compounds was found to demonstrate significant cytotoxicity for cultured human cancer cells, but 2-hydroxy-5-butoxyphenylacetic acid and 2,5-dihydroxyphenylacetic acid methyl ester gave EDso values of 1.0 and 1.7 #g ml-1, respectively, with cultured P-388 cells.