Background : Mahuang (Ephedrae Herba, Ephedra sinica $S_{TAPE}$) has been widely used to treat respiratory disease in Asian over the past thousand years. The main ingredient of Mahuang is ephedrine, whose affects on the autonomic nervous system induce some adverse effects like vasoconstriction, hypertension, tachycardia, miosis, insomnia, dizziness, headache, etc. Although there were lots of reports about adverse effects of Mahuang, there were no clinical studies which evaluated the adverse effects of Mahuang on the autonomic nervous system by objective numerical value in the past decade. Objectives : The purpose of this report was to provide an objective assessment of state-trait anxiety that is caused by Mahuang, and to identify anxiety of Mahuang according to different Sasang constitution classifications. Methods : The study design was a double-blind randomized placebo-controlled trial. The subjects of this study were 79 adults aged between 20 to 40 who agreed to participate. Because 8 adults dropped out, a total of 71 subjects entered the study. They were allocated through randomization to a Mahuang group (N=50) and placebo group (N=21). Each group took three opaque capsules (every opaque capsule containing 2g of Mahuang or none) twice a day. To compare the state and trait anxiety before and after taking Mahuang, we checked the anxiety by using STAI-KYZ. Results : The following results were obtained. Short-term administration of Mahuang significantly increased state-anxiety, but in the placebo group, there were no significant changes in state-anxiety. In the Mahuang group except females, there was more significant increase in state-anxiety of Soeumin than Soyangin and Taeumin in the 2nd measurement. Conclusion : It is suggested that the ingestion of Mahuang can increase sympathetic activity and induce anxiety. There was a significant difference among Sasang constitution classification. Especially, the response is stronger in Soeumin than other constitutions. If we use Mahuang according to the Sasang constitution classification in clinic, we could not only minimize the anxiety but maximize the potential curative value.