Prunella vulgaris L. aqua-acupuncture solution (PVAS) was tested for cancer chemopreventive activity using chemoprevention-associated biochemical end points. The following effects were measured. : (a) inhibition of 7,12-dimethylbenz[a]anthracene (DMBA)-induced cytochrome P4501A1 activity (b) inhibition of $[^3H]B[a]P-DNA$ binding (c) inhibition of phorbol 12-myristate 13-acetate (TPA)-induced free radical formation in HL-60 cells (d) inhibition of polyamine metabolism. PVAS inhibited cytochrome P4501A1-mediated ethoxyresorufin-O-deethylase activity. The binding of $[^3H]B[a]P$ metabolites to DNA of NCTC-clone 1469 cells was inhibited significantly by PVAS. There is 22% inhibition of TPA-induced free radical formation in human leukemic cells with 5 mg/ml PVAS. Proliferation of Acanthamoeba castellanii was inhibited by PAVS at concentration of 30 mg/ml. PAVS positive in these assays may inhibit the carcinogenesis process and is considered very promising cancer-preventing agent because of its multiple activities.