ABSTRACTThe bark of Pseudocedrela kotschyi is traditionally used by people in sub-Saharan regions to treat fever. The main objective of this study is to determine the antipyretic activity, phytochemical constituents with pharmacological potential, and toxicity of the aqueous extract of Pseudocedrela kotschyi stem bark. The comparative study of the aqueous extract of Pseudocedrela kotschyi stem bark with lysine acetylsalicylate on brewer's yeast-induced hyperthermia in rats revealed the antipyretic properties of this extract. The standard methods used for the qualitative analysis of phytochemical constituents revealed the presence of alkaloids, flavonoids, catechic tannins, saponosides, polyphenols, quinones, terpenoids, oses and holosides while coumarins and gall tannins are absent. The toxicological study of the aqueous extract of stem bark of Pseudocedrela kotschyi determined an LD 50 of 240 mg/kg BW. According to the classification of Diezi (1989), this plant is moderately toxic by the intraperitoneal route. These results justify traditional use of Pseudocedrela kotschyi bark against fever.Keywords: Pseudocedrela kotschyi-Lysine acetylsalicylate-Antipyretic.