RESUMO
<p><b>OBJECTIVE</b>Taking Caulis Aristolochiae Manshuriensis (Guanmutong in Chinese, derived from the stem of Aristolochia manshuriensis) as an example, to study the affection of different preparations on the content of toxic constituents in traditional Chinese medicines.</p><p><b>METHOD</b>The separation was performed on a zorbax SB-C18 column with mobile phase of acetonitrile-3.7 mmol x L(-1) phosphoric acid buffer, detected at 260 nm.</p><p><b>RESULT</b>The extraction percentage of aristolochic acids I, II and IV a in water extraction (1 h x 2) of Guanmutong were 53.4%, 75.5% and 61.9%, respectively; the remaining quantity of aristolochic acids I, II and IVa in the dregs of the decoction were 22.3%, 15.7% and 30.3%, respectively; Aristolochic acid I was still main substance among these aristolohic acids in the decoction of Guanmutong.</p><p><b>CONCLUSION</b>The content of toxic constituents of the traditional Chinese medicines varies evidently with different preparations of Guanmutong. So the preparation methods of traditional Chinese medicines should be suitably selected according to characteristics of the toxic constituents so as to lessen the body damages of human.</p>