The aims of this study were to examine the antiproliferation of Humulus lupulus extracts on human hepatoma carcinoma (Hep3B) and human colon carcinoma (HT-29) cell lines along with enzyme inhibitory effects of the crude extracts. Potential cell cytotoxicity of six different H. lupulus extracts were assayed on various cancer cells using MTT assay at 24, 48 and 72h intervals. Methanol-1 extract has inhibited the cell proliferation with doses of 0.6-1mg/mL in a time dependent (48 and 72 hours) manner in Hep3B cells with 70% inhibition, while inhibitory effect was not seen in colon cancer cells. Acetone extract has increased the cell proliferation at low doses of 0.1mg/mL for 72h in Hep3B cells and 0.1-0.2mg/mL for 48 and 72h in HT29 cells. The inhibitory effects of the extracts were compared by relative maximum activity values (V-max) using proteases such as -chymotrypsin, trypsin and papain, tyrosinase and -lactamase (penicillinase).