ABSTRACT
<p><b>OBJECTIVE</b>To study the different and the variety of four organic acids in leaves of Isatis indigotica among different cultivated populations in water stress condition and healthy plant.</p><p><b>METHOD</b>Four kinds of organic acids, such as oxalic acid, malic acid, ascorbic acid and citric acid from the leaves, were detected by HPLC.</p><p><b>RESULT</b>Significant differences of four organic acids in the leaves of Beijing, Mongolia, Hebei and Shanxi cultivated populations. Compared with the healthy plant, the content of oxalic acid, malic acid and citric acid in water stress were increased, while the content of ascorbic acid was decreased.</p><p><b>CONCLUSION</b>Contents of four organic acids can act as the guideline factor in I. indigotica because they were related with the water stress condition.</p>