Attempts were made to see the antitumor effects of Sigbunhwan widely used in Oh-jug(五積) employing tumor cells Lines such as K562 derived from erythroleukemia, Raji from lympoma and MO-4 from blastogenic tumor. Different concentrations of Sigbunhwan and combined therapy of Sigbunhwan and Bigihwan were treated to those tumor cells lines and then live cells were counted by Trypan blue assay and $^{3}H-Thymidine$ uptake assay. The results obtained were as follows. 1. $^{3}H-Thymidine$ uptake of various tumor cells lines when treated with high concentrations of Sigbunhwan for 48hours showed that the rate of DNA synthesis decreased 76% to 90% by the treatment of 1% Sigbunhwan but this inhibition was rather decreased when Sigbunhwan concentration was increased to 10, 15 and 20%.(Fig 3) 2. When Sigbunhwan was combined with Bigihwan which was also an antitumor drug, the effectiveness of tumor cells dealth was somewhat inceased showing a generally similar pattern to that of Bigihwan alone used.(Fig 4) This combination therapy also showed that higher concentrations of antitumor agent were no more·effective or rather harmful according to the tumor cells lines having different growth rate.(Fig 5,6) 3. The antitumor effects of combined Sigbunhwan and Bigihwan was decreased if the concentrations of this combination therapy was increased to 10 times showing relatively sluggish decrease in K562 and MO-4 but a sharp inhibitory effect in Raji which grows slowly.(Fig 7). 4. When Sigbunhwan was treated at low concentrations, K562 was more inhibited by 0.75% to 1.0% of Sigbunhwan while Raji was more inhibited by 0.25% to 0.5% of that.(Fig 8) 5. When Sigbunhwan was treated together with Bigihwan at low concentrations, the tumor cells death rate was 75% to 89% in Baji, 31% to 95% in MO-4 and 41 to 89% in K562, showing this combination therapy was more effect to Raji derived from lymphoma.(Fig 9) 6. The number of live tumor cells was correlated with optical density of MTT assay when measured with 2% Sigbunhwan treatment to tumor cells lines for 24 hours.(Fig 10) 7. 7 days treatment of 0.25% Sigbunhwan was compared with one day treatment of 1% suggesting long term treatment more effective.(Fig 11)