Commercially grown Acala cottons (Gossypium hirsutum L.), like most other species of the genus Gossypium, have evolved an effective chemical resistance that deters most plant-feeding animals. The biologically toxic component is a group of related, secondary plant metabolites known as terpenoids. Gossypol, the best known of these terpenoids, is a polyphenolic yellow pigment closely associated with the epidermal glands present on all aerial plant parts as well as in the cottonseed. Most commercial cottonseed contains about 1 percent gossypol, depending on variety and environmental conditions. Expensive chemical and physical procedures are used to remove gossypol from cottonseed products destined for use as food for non-ruminant animals.