AbstractKhaya grandifoliolastem bark extract was tested for antimalarial action againstPlasmodium berghei bergheiin mice. The schizontocidal activity of the extract was assessed on early and established infections using chloroquine as a standard drug. The repository activity was also investigated and pyrimethamine was used as the standard. In the early infection test (like the chloroquine group),K. grandifoliolaextract was effective in suppressing the malaria infection. However, on the established infection, the extract failed to effectively suppress the infection. The extract also demonstrated residual activity.