Gamdutang aqua-acupuncture solution(GAS) and Gamdutang water-extracted solution(GWS) were prepared and tested for potential antitumor activites. It was shown to possess considerable toxicity toward various tumor cell lines. Concentration of $5{ imes};and;10{ imes}$ of GAS resulted in more than 70% inhibition of growth in Ehrlich ascites tumor cells(EATC), hepa1c1c7 and A549. GAS at the concentration of $10{ imes};and;5{ imes}$ revealed that more than 60% inhibition in HeLa. GWS showed more than 50% in hibition of growth with EATC, HeLa at the concentration of $5{ imes};and;10{ imes}$. Toxicity assay with GWS in hepa1c1c7 and A549 revealed that more than 80% inhibition in growth at the concentration of $5{ imes};and;10{ imes}$. In morphological study, the number of cells were decreased, and the shape of cells was round-form. Most of cells in detached in EATC, Hepa1c1c7, HeLa, and A549 with GAS. These results suggest that GAS has antitumor activity in vitro.