Malarone belongs to a group of medicines called antimalarials. It contains two active ingredients, atovaquone and proguanil hydrochloride. Malarone has two uses one to prevent malaria and the other is to treat malaria. Malaria is spread by the bite of an infected mosquito, which passes the malaria parasite (plasmodium falciparum) into the bloodstream. Malarone prevents malaria by killing this parasite. For people who already infected with malaria, Malarone also kills these parasites.