The crude extract from the bark and seeds of Khaya grandifoliola was active in vitro against Plasmodium falciparum with an IC50 value of 13.23 microg/ml. The extract was purified to obtain seven limonoids--methylangolensate (1), 6-methylhydroxyangolensate (2), gedunin (3), 7-deacetylkhivorin (5), 1-deacetylkhivorin (6), swietenolide (7), 6-acetylswietenolide (8)--and one flavonoid, catechin (4). Five limonoids (1, 3, 5, 6, 8) were active with IC50 values between 1.25 and 9.63 microg/ml. Catechin was practically devoid of activity. The most active limonoid, gedunin, exhibited an additive effect when combined with chloroquine.