The decoction of Cynanchum glaucescens and the ethanol extract of C. stauntonii show significant antitussive and expectorant actions. The decoctions of C. stauntonii or C. glaucescens have antiasthmatic and anti-inflammatory effects. The decoction of C. atratum has some expectorant effect but no antitussive or antiasthmatic actions. On the other hand, the decoction of C. versicolor cannot relieve cough nor sputum. The results indicate that both C. atratum and C. versicolor cannot be used as C. glaucescens or C. stauntonii.
Adolescent Animals