Drugs that treat an infection caused by a bacterium, virus, fungus, or protozoan parasite and act throughout the body, following ATC Group J (Antiinfectives for Systemic Use). Belongs here: an antibiotic, an antiviral, an antifungal, and an antimalarial, each named for the class of organism it targets. Does not belong here: an antiparasitic agent aimed at a multicellular parasite such as a worm, grouped under antiparasitic agents, and a topical antiinfective applied only to the skin rather than acting systemically.