Alchornea cordifolia (Euphorbiaceae) is widely used in Africa for the treatment of malaria, fever, tooth decay, leprosy, amoebic dysentery, hemorrhoids, headaches, venereal diseases and inflammation. It is also used as emmenagogue and oxytocic. Quassia africana (Simaroubaceae) is also widely used in Africa for the treatment of malaria, gastritis, intestinal worms, rheumatism, bronchopneumonia, gonorrhea, headache, tooth decay and tonsillitis. The present study aims to highlight the analgesic and antipyretic effects of both plants. Fever was induced by oral administration of 20 ml / kg of 20% beer yeast in rats 24 hours before treatment. The rectal temperature was measured 1h, 2h and 3h after treatment. The pain was induced by intraperitoneal injection of 0.1 ml / 10 g of 0.6% acetic acid in rats 1 hour after oral treatment. The analgesic activity was assessed for 10 minutes by counting the number of cramps. The aqueous, ethanolic and dichloromethane extracts of the leaves and fruits of Alchornea cordifolia at 400 and 800 mg / kg per os showed a very significant antipyretic effect identical to paracetamol at 100 mg / kg per os. The aqueous extracts of the leaves and fruits of Alchornea cordifolia as well as barks of Quassia africana at 400 and 800 mg / kg per os showed a very significant analgesic effect. These effects are related to the presence of alkaloids and terpenes for Alchornea cordifolia and Quassinoides for Quassia africana.