AIM To study the pharmacokinetics of bromotetrandrine (W198) in rats and beagle dogs. METHODS The concentrations of W198 in serum were determined using HPLC method with UV detection. RESULTS The pharmacokinetic parameters of W198 after single iv doses of W198 10, 20 and 40 mg x kg(-1) in rats were as follows: T1/2beta were 6.60, 7.36 and 6.77 h, AUC0-24 h were 3.797, 7.371 and 15.192 mg x h x L(-1), Vd were 7.14, 4.33 and 4.13 L x kg(-1), CL were 2.83, 2.60 and 2.71 L x (kg x h)(-1), respectively. The T1/2beta and AUCo-24 h of W198 after single im dose of W198 20 mg x kg(-1) in rats were 11.61 h and 12.646 mg x h x L(-1). The im bioavailability of W198 in rats was 56.9%. The T1/2beta, AUC0-24 h, Vd and CL of W198 after single iv dose of W198 5 mg x kg(-1) in beagle dogs were 11.72 h, 12.646 mg x h x L(-1), 0.70 L x kg(-1) and 0.46 L x (kg x h)(-1), respectively. The plasma protein binding ratio of W198 with human serum protein was 78.0%. CONCLUSION The absorption of W198 in rats was of first order kinetics.