ABSTRACT
<p><b>OBJECTIVE</b>The pulmonary toxicity of water extract of Siegesbeckia pubescens has been studied an mice following subchronic oral administration route.</p><p><b>METHOD</b>Mice were randomly grouped and administered with the water extract of S. pubescens at dosages of 3.0, 1.0, 0.3 g x kg(-1) and saline respectively. 10 mice of each group were sacrificed on the day of 7 th, 14 th, 21 th, and 2 weeks after stopping administration, histological changes of the lung were examined.</p><p><b>RESULT</b>The water extract of S. pubescens at dosage of 3.0 g x kg(-1) increased the lung index on the of day 14 th and 21 th, significant histopathological damages were observed. The histopathological changes were disappeared after stopping administration for 2 weeks.</p><p><b>CONCLUSION</b>The water extract of S. pubescens has a pulmonary toxic effect on mice, and the toxic effect is reversible.</p>