This study was carried out to find new antitumor agents from plant resource. Three cytotoxic agents were isolated from the root of Dictamnus albus by hexane extraction, silica gel column chromatography and HPLC. They were identified to be dictamnine $(C_{12}H_9NO_2)$, preskimmianine $(C_{17}H_{21}NO_4)$ and fraxinellone $(C_{14}H_{16}O_3)$ on the basis of spectroscopic evidences. In this study, it was newly found that these compounds possess a cytotoxic activity against lung lymphoma L1210 cell line. Among them. Preskimmianine was the most potent against the lymphoma L1210 with a $IC_{50}$ of $3.125;{mu}g/ml;(10.3;{mu}M)$. Toxicity of preskimmianine against normal Iymphocyte was observed at the concentration of $50;{mu}g/ml;(165;{mu}M)$. These results support the pharmacological role of D. albus, a herb known as Paeksun in Korea and used as an anticancer agent in folk medicine.