Proguanil is a synthetic biguanide specialty chemical primarily used as an antimalarial agent in pharmaceutical applications. It is often combined with atovaquone (as in Malarone) or chloroquine to prevent and treat malaria by inhibiting the development of the Plasmodium parasite in the liver and red blood cells. As a prophylactic, it is prescribed for travelers to malaria-endemic regions. It is also effective in areas with resistance to other antimalarials. Its low cost and efficacy make it valuable in global malaria control programs. Proguanil may be used for treating uncomplicated malaria when other options are unsuitable. In laboratory and research settings, high-purity proguanil (≥99%) serves as a reagent for studying antimalarial mechanisms, drug synthesis, and pharmacological assays.