Abstract: To investigated the polyherbal formula (Joloo) for its antimalarial and anti-pyretic properties on mice and rats. In the antimalarial study mice were infected with Plasmodium berghei using three doses (1600, 800 and 400 mg kg-1 b.wt.). Pyrexia was induced in the rats by the administration of 10 mg kg-1 b.wt., of 2,4-Dinitrophenol intraperitoneally while measurement was by inserting a clinical thermometer into their anal cavities for about 2 min. Chloroquine and acetylsalicylic acid were used as reference drugs in mice and rats respectively, while water served as control for both. The antiplasmodial study involved two phases; the suppressive where mice were administered plant extract per os for four days immediately after inoculation and blood smear prepared on the fifth day and the curative phases where mice were inoculated with parasites three days before administration of extract so as to allow for full development of parasites. They were administered the extract orally for five consecutive days and blood smears prepared during the period of administration and five days post administration. During the 5-days suppressive study, the herbal formulation (Joloo) showed significant daily dose-dependent decrease in parasitaemia and compared favourably with the reference drug (Chloroquine). It was observed however that the 1600 and 800 mg achieved a total 100% chemosuppression of parasitaemia, while 400 mg kg-1 b.wt. dose was 44.5%. During the curative study, there was significant dose-dependent decrease in parasitaemia during the 5-days period of administration and subsequent increase in parasitaemia in the remaining 5-days post administration. In both suppressive and curative assays, chloroquine achieved 100% chemosuppression while Joloo achieved 100% chemosuppression in the suppressive assay. Besides, Joloo inhibited parasitaemia only during administration in the curative study after which a progressive increase in parasitaemia was observed during post-administration. In the anti-pyretic study, Joloo significantly reduced hyperthermia in rats dose-dependently. This clearly suggests that Joloo contain biologically active substances with the potential of managing and treating malaria and fever. It provides scientific evidence to support the isolation and development of biologically active components as anti-malarial and antipyretic agents.