A simple HPLC method had been developed and validated to quantify Z-3,5,4'-trimethoxystilbene (Z-TMS), a phyto-stilbene with potent anti-cancer activities in rat plasma. Chromatographic separation was achieved on a reversed phase-HPLC column, which was protected by a guard column through a 13.5-min gradient delivery of a mixture of acetonitrile and water at a flow rate of 1.5 ml/min at 50 degrees C. The UV absorbance at 300 nm was recorded. Z-TMS and E-stilbene (internal standard) eluted at 8.8 and 9.3 min, respectively. The calibration curve was linear within the range of 33-2500 ng/ml (R(2)>0.9995) and 10 ng/ml was the lower limit of detection. The intra- and inter-day precisions were good and the relative standard deviation was all lower than 10%. The analytical recovery of Z-TMS in plasma ranged from 94.6+/-9.1% to 97.0+/-2.1%. This HPLC method was successfully applied to assess the pharmacokinetic profile of Z-TMS in Sprague-Dawley rats using hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) as a dosing vehicle. Although Z-TMS displayed negligible oral bioavailability, it had a fairly long terminal elimination half-life, abundant plasma drug exposure and limited clearance following intravenous administration. As Z-TMS had favorable intravenous pharmacokinetic profile, further investigation on its potential as a cancer chemotherapeutic agent is warranted.