The influence of gibberellic acid on the quality of fixed oils from four plants has been studied. Sesame, castor bean, sunflower, and flax plants were treated with aqueous solutions of gibberellic acid when the plants reached blooming size and at 2-week intervals until harvest. The iodine values and the quantity of unsaponifiable matter varied between samples and between oils from different species of plants. Significant variations from normal were produced in castor and sesame oils. The differences consisted of higher saponification values in both oils and a lower acid value in the latter. A higher saponification value indicating shorter chain fatty acids was the only characteristic common to all oils from treated plants. Some of the changes obtained were from plants that had insignificant or no visible morphological differences. The influence of gibberellic acid on the quality of fixed oils from four plants has been studied. Sesame, castor bean, sunflower, and flax plants were treated with aqueous solutions of gibberellic acid when the plants reached blooming size and at 2-week intervals until harvest. The iodine values and the quantity of unsaponifiable matter varied between samples and between oils from different species of plants. Significant variations from normal were produced in castor and sesame oils. The differences consisted of higher saponification values in both oils and a lower acid value in the latter. A higher saponification value indicating shorter chain fatty acids was the only characteristic common to all oils from treated plants. Some of the changes obtained were from plants that had insignificant or no visible morphological differences.