Context: Solenostemon monostachyus P. Beauv (Lamiaceae) is an important herb used traditionally in the treatment of malaria, fever, and other diseases. Objectives: Antiplasmodial and antipyretic activities of S. monostachyus aerial extract were evaluated to ascertain the folkloric claim of its antimalarial and antipyretic activities. Materials and methods: The extract (75-225 mg/kg) and fractions (chloroform and aqueous; 150 mg/kg) of S. monostachyus were investigated for suppressive, prophylactic, and curative antiplasmodial activities against chloroquine-sensitive Plasmodium berghei infections in Swiss albino mice and for antipyretic activity against 2,4-dinitrophenol and yeast-induced pyrexia. Artesunate (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls for antiplasmodial models. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice.