Background and purpose: Site-direct delivery is a desirable and elusive goal. In Traditional Chinese Medicine, this goal is usually met by coadministration with a kind of meridian guide drug (MGD). Vinegar-baked Radix Bupleuri (VBRB) is usually used to focus other drugs pharmacological effect on liver in Traditional Chinese Medicine (TCM). However, the scientific data for this effect are not available. In this paper, the liver targeting enhancing effect of VBRB on resveratrol was investigated. Experimental approach: Mice, 144, were divided into four groups by random, resveratrol group as control and resveratrol coadministered with three different doses of VBRB peroral. Concentrations of resveratrol in different tissues were determined by HPLC and the target effeciency was evaluated by relative uptake efficiency (RUE) and relative targeting efficiency (RTE). Key results: Compared to the control group, medium dose VBRB enhanced the targeting efficiency of resveratrol significantly, and the RUE and RTE were 1.79 and 46.9%, respectively. Meanwhile, it considerably reduced the distribution of resveratrol in lung and blood, the RUE and RTE in blood were 1.1, -22.6%, and were 0.88, -55.0% in lung, respectively. VBRB reduced the Cmax of resveratrol in almost all the tissues except for liver, heart and kidney, with the extent in the range of 26-61%. In addition, VBRB prolonged the retention time of resveratrol in liver, and shortened the retention time in other tissues. Conclusions and implications: VBRB could enhance the distribution of resveratrol in liver, and reduce the distribution in other tissues, implying that VBRB might be a potential drug for achieving target therapy. (C) 2009 Elsevier Ireland Ltd. All rights reserved.