The bioavailabilities of baicalin in water, oil, w/o and o/w emulsion were evaluated in rats. The dissolution rate of baicalin in o/w emulsion was smaller than those of w/o form in dilute hydrochloric acid solution (pH 1.2) and in PBS (pH 6.8). The absorption rate of baicalin from w/o emulsion was smaller than that of o/w emulsion in the different parts of rat intestine of the rats. Following oral administration in rats, the $C_{max}$ of baicalin from water phase, oil phase, o/w wand w/o emulsion were 2.11, 0.61, 1.57, and $1.35;{mu}g/ml$, respectively. The relative bioavailability of w/o emusion was 129 % when it was compared with water phase. This result suggests that the improvement of bioavailability for baicalin in w/o emulsion might be practically available.