Antimalarial drugs are used for the treatment and prevention of malaria infection. Most antimalarial drugs target the erythrocytic stage of malaria infection, which is the phase of infection that causes symptomatic illness. Treatment of the acute blood stage infection is necessary for malaria caused by all malaria species. The mechanisms of action, resistance, and toxicities of antimalarial drugs will be reviewed here. Use of these agents for prevention and treatment of malaria is discussed in detail separately. Chloroquine was the first drug produced on a large scale for treatment and prevention of malaria infection