Arteflene is the sesquiterpene peroxide. It is a synthetic derivative of yingzhaosuwas. Arteflene found negative in a battery of mutagenicity tests. It had low acute toxicity after oral or subcutaneous administration in pre-clinical studies. Experimentally arteflene proved to be a highly effective antimalarial drug. An open, non-comparative clinical trial was carried out in Nigeria and Burkina Faso to investigate the safety and efficacy of the arteflene in patients with mild malaria. The lower than expected effect was thought to be due to inadequate storage of the arteflene suspension. There were no withdrawals due to adverse events and no deaths. Arteflene had no major effect on TNF, IL-alpha or IL-6 cytokine release from mononuclear cells stimulated with malaria antigens or lipopolysaccharide and it did not affect cell viability. Arteflene only slightly suppressed cytoadherence of infected erythrocytes to melanoma cells. The therapeutic effect of Arteflene appears to be confined to its parasite killing activity. Single dose monotherapy with arteflene was not effective in curing children suffering from uncomplicated P. falciparum malaria in Gabon. Arteflene is reported to be more cytotoxic to primary rat hepatocytes than some non-endoperoxide antimalarials.