The pharmacokinetics of Guanfu base I in Sprague-Dawley rats were examined, showing linearity in the 0.05-20 μg/mL concentration range with recovery exceeding 80%. Intraday and interday precision, as relative standard deviation, were generally good. Following intravenous injection, plasma Guanfu base I concentration declined bi-phasically with a terminal elimination half-life of 2.49 hours and a total plasma clearance of 1.46 L/h/kg. After oral dosing, the plasma concentration peaked within 0.5 hours, and the absolute bioavailability was 71.31%.