The purpose of the present study was to examine the pharmacokinetic characteristics of erianin (2-methoxy-5-[2-(3,4,5-trimethoxyphenyl)-ethyl]-phenol, CAS 95041-90-0), a nature product extracted from Dendrobium chrysotoxum, having notable antitumour activity, after intravenous injection of erianin fat emulsion to beagle dogs. An HPLC-MS method was developed to analyze the erianin levels in dog plasma and validated in a pharmacokinetic study. Plasma profiles were obtained after intravenous injection of erianin fat emulsion at the doses 7.5, 15 and 30 mg/kg. The elimination half-life (t(1/2)) values for erianin were estimated to be 1.41+/- 0.31, 1.66 +/- 0.19, 1.60 0.28 h, while the mean area under concentration-time curve (AUC(0-infinity)) values were 1021.3 +/- 373.7, 2305.1 +/- 597.0 and 3952.1 +/- 378.2 ng x h/ml, respectively. In conclusion, the present observations indicated that erianin plasma concentrations were clearly dose-proportional for the dose range studied. There was no gender difference in pharmacokinetics for erianin in male and female dogs.