Abstract: OBJECTIVE To study the possibility of Elsholtzia densa become an enhancer of herb medicine through the examination on the percutaneous absorption of volatile oil from Elsholtzia densa.METHODS transdermal experiment in vitro was used to investigate the enhancing permeation effect of the volatile oil from Elsholtzia densa to baicalin. The abdominal skin of KM mice was the object of study. The content of baicalin in the receptor fluid was determined by HPLC, in order to calculate the cumulative penetration quantity of baicalin. RESULTS The enhancing permeation effect was best, and the cumulative permeation of baicalin was the largest, when the content of the volatile oil was 3%. Compared with the positive control of azone, the cumulative penetration quantity of volatile oil from Elsholtzia densa was higher than azone.CONCLUSION Volatile oil of Elsholtzia densa have the function of percutaneous absorption, it can improved the absorption of Baicalin.