In a preliminary research, the authors reported that solvents extracts of Alstonia boonei (Egbu) possess strong antimalarial activity against NK-65 Chloroquine sensitive Plasmodium berghei infected mice with aqueous extract having the highest decrease in mean percentage parasitaemia. This research is therefore aimed at evaluating the acute and sub-chronic toxicity of solvents extracts of the plant on kidney. The (LD50, oral) was conducted in two phases. In the first phase, oral doses of 10, 100 and 1000 mg/kg body weight of the extracts were administered and mice observed for sign of toxicity and death. In the second phase, 1600, 2900 and 5000 mg/kg body weight of the extracts were administered and signs accompanying toxicity and possible death of animals were also monitored. Sub-chronic toxicity studies were carried out to assess the effect of the solvents extracts on kidney function indices after 28 days of oral administration of the extracts at 150, 250 and 500 mg/kg body weight. The (LD50, oral) of all extracts was found to be greater than 5000mg/kg which is practically non- toxic according to standard scale of toxicity. The result of sub-chronic toxicity study showed a significant increase (P<0.05) in mean levels of creatinine, urea and serum electrolytes in all extracts administered groups in a dose dependent pattern compared to normal control. However, histopathological analysis of the kidney tissues shows no pathological changes between test groups and normal control. Thus, solvents extracts of Alstonia boonei modifies biochemical parameters (Crea, Urea and Electrolytes) but within the context of duration of this research, no significant pathology was observed in kidney tissues. Alstonia boonei stem bark should be used with caution