Objective: To investigate feasibility of UV and co-chromatography for evaluating in vitro dissolution of Chinese medicine preparations. Method: With 0.1 mol·L-1 hydrochloric acid as release medium

in vitro dissolution of Xiaochaihu tablets was determined according to the 2005 edition of 'Chinese Pharmacopoeia'

absorbance of release solution at 272 nm was determined by UV

the content of baicaline was determined by HPLC.UV absorption ingredients of this solution were divided into two parts—the defined ingredient (baicaline) and the undefined ingredients (other ingredients). Result: HPLC could reflect dissolution of baicaline(the defined ingredient);UV could describe dissolution of other ingredients through deducting UV absorption of baicaline from release solution. Conclusion: In vitro dissolution of Chinese medicine preparations could be better measured and assessed by co-chromatography and UV.