Three azedarachins, insect antifeedant limonoids, have been isolated from the root bark of Chinese Melia azedarach Linn (Meliaceae), along with six trichilins. Their structures show a 14,15-epoxide and a 19/29 acyl acetal bridge system, as elucidated by spectroscopic studies. They are antifeedants active against the larvae of Spodoptera exigua Hubner (Boisduval).