<正> An active antimalarial fraction of the Chi-nese herbal drug Qinghao (Artemisia annua L.)was isolated in 1971,from which a new ses-quiterpene peroxide was isolated the followingyear,structure and absolute stereochemistryhaving been definitely established.Based onpharmacological and clinical studies this wasshown to be the antimalarial principle and wasnamed Qinghaosu (Artemisinine),referred toalso as QHS.