Artemesenin (sweet wormwood, or quinghasou in Chinese) is an extract of Artemesia annua. Artemisia is a large, diverse genus of plants with between 200-400 species belonging to the daisy family Asteraceae which comprises hardy herbs and shrubs known for their volatile oils.

Artemesinin has been used successfully to treat the most serious species of malaria, P. falciparum, in Thailand, Vietnam, and more recently in Africa. It rapidly clears the parasites from the bloodstream in a few days, but if not taken with a second, effective antimalarial drug, there is a high rate of recurrence of the disease. It appears to be a non-toxic drug, but has not been fully studied and caution is required for use during pregnancy.

Artemesinin derivatives should not be taken regularly for the suppression or prevention of malaria. The World Health Organization recently announced* agreement among the major drug manufacturers to stop producing artemesinin-only products because of the high rate of development of drug-resistant parasites when this compound is not used in conjunction with another antimalarial. Also, there have been reports of impaired hearing after use of these products.

Artemesinin derivatives should not be to treat an attack of malaria without a second, effective anti-malarial drug., although it has the usefulness described above. Preparations of the drug vary in strength, the frequency of administration required to effectively clear the parasites is unknown, and the emergence of resistant parasites is favored. Prompt treatment by a health care provider experienced in treating this disease is necessary to completely clear all the parasites from the body, as relapse of the life-threatening illness is likely. NOTE: there is now reported resistance to artemesinin along the Thai-Cambodia border.

Persons who travel to malarious areas of the world who wish to avoid the most serious, potentially fatal consequences of infection with P. falciparum should pay close attention to the personal protection measures to avoid all biting insects, and use one of the suppressive anti-malarials known to be effective for the region they intend to visit.