Ephedrae herba(Ma-huang) has been used to treat respiratory conditions for over 5,000 years. The early 1990s, the herbal ephedra and other products containing ephedrine began to be promoted as weight loss aids in United States. The objective of this study was to evaluate the acute toxicity of hebal ephedra in rats. SPF Sprague-Dawley male and female rats were administered orally with herbal ephedra extract of 2,500 mg/kg(low dosage group), and 5,000 mg/kg(high dosage group). We daily examined number of deaths, clinical signs, body weights and gross findings for 14 days. No dead animal and no significant changes of body weights were found during the experimental period. In addition, no differences were found between control and treated groups in clinical signs, hematology, serum biochemistry, and other findings. In conclusion, herbal ephedra extract did not show any toxic effects and oral LD50 value was over 5,000 mg/kg in SD rats.