The leaves of Pseudocedrela. kotschyi are used in herbal medicine in Sub-Saharan Africa without safety concerns. Determination of its safety profile will provide supportive scientific evidence in favour of its continuous usage. To evaluate the sub-chronic toxicity activity of the ethanol extract of Pseudocedrela. Kotschyi leaves. Sub-chronic toxicity evaluation of the extract was determined by administering 100 mg/kg, 200 mg/kg and 400 mg/kg on Wistar rats for 40 days with distilled water as control. The haematological and biochemical parameter as well as the relative organ weights were examined. In the 40 days sub-chronic oral toxicity study, administration of 100 mg/kg, 200 mg/kg and 400 mg/kg of P. kotschyi leaf extract per body weight showed significant (p<0.05) body weight change, significant (p<0.05 and p<0.01) changes in some haematological and biochemical parameters and organ weights compared to the control group. Analyses of these results could lead to the conclusion that the oral administration of P. kotscyi leaf extract for 40 days does not cause sub-chronic toxicity in rats