Used primarily in the treatment of malaria, especially Plasmodium falciparum infections. It is a key active metabolite of artemisinin derivatives and forms the basis of artemisinin-based combination therapies (ACTs), which are recommended by the WHO as first-line treatment for uncomplicated malaria. Due to its rapid action, it quickly reduces parasite load in the blood. Also being studied for potential antiviral and anticancer properties, particularly in preclinical models showing activity against certain tumor cells. Its short half-life requires combination with longer-acting antimalarials to ensure complete clearance of infection.