本文测定健康儿及重症肺炎和重度哮喘儿血浆内皮素－１（ＥＴ－１），结果重症肺炎及重度哮喘儿治疗前血浆ＥＴ－１均较健康儿明显升高，治疗后重症肺炎儿血浆ＥＴ－１降至正常，而重度哮喘儿血浆ＥＴ－１虽有所下降，但仍高于正常对照组，亦较重症肺炎组高（Ｐ＜０．００１）。提示ＥＴ－１参与了重症肺炎及重度哮喘的病理生理变化，是重症肺炎及重度哮喘发病的重要促发因素之一，还可能在哮喘气道变应性炎症过程中起一定作用。 The results of plasma ET-1 in children with severe pneumonia and severe asthma showed that plasma ET-1 in children with severe pneumonia and severe asthma were significantly higher than those in healthy children. After treatment, severe pneumonia children with plasma ET -1 decreased to normal, while severe asthmatic children plasma ET-1 despite the decline, but still higher than the normal control group, also heavier pneumonia group (P <0.001). It is suggested that ET-1 is involved in the pathophysiological changes of severe pneumonia and severe asthma, which is one of the most important contributors to severe pneumonia and severe asthma. It may play a role in airway allergic inflammation in asthma.