Artemisinin also known as Qinghaosu (Chinese), and its derivatives are a group of drugs that possess the most rapid action of all current drugs against Plasmodium falciparum malaria.Treatments containing an artemisinin derivative (artemisinin-combination therapies, ACTs) are now standard treatment worldwide for P. falciparum malaria. The starting compound artemisinin is isolated from the plant Artemisia annua, sweet wormwood, an herb employed in Chinese traditional medicine.
Chemically, artemisinin is a sesquiterpene lactone containing an unusual peroxide bridge. This peroxide is believed to be responsible for the drug's mechanism of action.

Use of the drug by itself as a monotherapy is explicitly discouraged by the World Health Organization, as there have been signs that malarial parasites are developing resistance to the drug. Therapies that combine artemisinin with some other antimalarial drug are the preferred treatment for malaria and are both effective and well tolerated in patients. The drug is also increasingly being used in Plasmodium vivax malaria,[3] as well as being a topic of research in cancer treatment.

Function:
Cancer treatment
Artemisinin is undergoing early research and testing for the treatment of cancer.Chinese scientists have shown artemisinin has significant anticancer effects against human hepatoma cells.Artemisinin has a peroxide lactone group in its structure, and it is thought that when the peroxide comes into contact with high iron concentrations (common in cancerous cells), the molecule becomes unstable and releases reactive oxygen species. It has been shown to reduce angiogenesis and the expression of vascular endothelial growth factor in some tissue cultures. Recent pharmacological evidence demonstrates the artemisinin-derivative dihydroartemisinin targets human metastatic melanoma cells with induction of NOXA (phorbol-12-myristate-13-acetate-induced protein 1)-dependent mitochondrial apoptosis that occurs downstream of iron-dependent generation of cytotoxic oxidative stress.
Helminth parasites
Serendipitous discovery was made in China while searching for novel anthelmintics for schistosomiasis. Artemisinin and its derivatives are all potent anthelmintics.Artemisinins were later found to possess a broad spectrum of activity against a wide range of trematodes, including Schistosoma japonicum, S. mansoni, S. haematobium, Clonorchis sinensis, Fasciola hepatica and Opisthorchis viverrini. Clinical trials were also successfully conducted in Africa among patients with schistosomiasis.