The objective of this chapter is to introduce the antimalarial drugs. 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. This chapter covers the artesunate, mefloquine, chloroquine, and hydroxychloroquine along with their indication, dose, contraindication, precaution, adverse effect, and drug interaction. Malaria and nonintestinal amebic infection are the indications of chloroquine. Hypersensitivity to 4-aminoquinoline compound, retinal/visual field changes are the contraindications of chloroquine.