Bufotalin is one of the active antitumor components in Ch'an Su which is a widely used traditional Chinese medicine. However, there is insufficient information on the biopharmaceutical properties of bufotalin based on pharmacokinetic studies. To investigate the pharmacokinetics and tissue distribution of bufotalin, single-bolus injection and constant-rate infusion of bufotalin solution were performed in mice. After single intravenous administration, bufotalin was quickly distributed and eliminated from the plasma with a t1/2 of 28.6 min and an MRT of 14.7 min. Bufotalin concentrations in brain and lung were significantly higher than those in blood and other tissues at 30 min after dosing. The steady-state bufotalin plasma concentration and tissue distribution were determined using a novel constant-rate infusion device, and the distribution characteristics were similar to those of single-bolus injection. These results indicated that bufotalin could cross the blood-brain barrier and naturally target the lung. Bufotalin might be a promising antitumor candidate for lung cancer.