Objectives The aim of this study is to investigate whether hwang-ryun-haedok-tang (HDT) affect proliferations of androgen-dependent LNCaP prostate cancer cells, androgen-independent PC-3, DU-145 prostate cancer cells, MCF-7 human breast cancer cells, A549, NCI-H292 human pulmonary cancer cells and K-562 human chronic myelogenous leukemia cells. Materials and Methods Effects of HDT on proliferations of each cancer cell line were investigated. 20,000 cells/well were plated in each well of 96-well culture plate. After 24 hrs, 0.01-10% of HDT in culture medium was added to cancer cells. The number of cells was counted by using SRB assay or direct cell counting method after 72 hours from drug treatment. Effect of baicalein or berebrine on proliferation was assessed according to the same method. Results (1) HDT inhibited proliferations of LNCaP, PC-3 and DU-145 prostate cancer cells. (2) HDT inhibited proliferation of MCF-7 breast cancer cells. (3) HDT also inhibited proliferations of A549, NCI-H292 pulmonary cancer cells and K-562 chronic myelogenous leukemia cells. (4) Baicalein and berberine also showed inhibitory effects on proliferations of prostate and breast cancer cells. Conclusion : HDT inhibited proliferations of human prostate, breast, pulmonary and blood cancer cells. These results suggest us the potential use of HDT as a chemopreventive or chemotherapeutic agent. Effect of HDT on human cancer should be further investigated using in vivo experimental models that can reflect pathophysiology of human cancer through another studies.