To study the compounds from the fruits of Leonurus japonicus and their anti-proliferation of liver cancer cells and hepatocyte protection activities.Macroporous adsorbent resin (D-101) column chromatography,silica gel column chromatography,reversed phase C₁₈ column chromatography,and high performance liquid chromatography were used for separation and purification of the compounds.The structure of each compound was identified by organic spectroscopy.Three 8-O-4′ neolignans were isolated from the fruits of L. japonicus,which are (+)-(7S,8S,7′E)-4,9,9′-trihydroxy-3,3′,7-trimethoxy-8-O-4′-neolignan (1),7,8-threo-methyl-4-［2-hydroxy-2-(4-hydroxy-3-methoxyphenyl-)1-(hydroxymethyl)ethyl］ferulate(2),7,8-erythro-methyl-4-［2-hydroxy-2-(4-hydroxy-3-methoxyphenyl-)1-(hydroxymethyl)ethyl］ferulate(3).We first reported the absolute configuration of compound 1.Compound 3 is a new natural product.Both compounds 1,2 and 3 were isolated from the fruits of  L. japonicus for the first time.The anti-proliferation of liver cancer cells and hepatocyte protection activities of each compound were investigated by the MTT method.When the three compounds were administered at a concentration of 50 μmol/L,they had no obvious inhibitory effect on inhibition proliferation of SMMC-7721 liver cancer cells and no obvious protective effect on acetaminophen-injured Chang and HL-7702 liver cells.