The recent trend toward increased use of polyunsaturated vegetable oils in the human diet has emphasized the need for better antioxidant systems than those currently available. This need led to a research program in which a variety of experimental antioxidants were evaluated. Their selection was influenced by general requirements for food additives and by the resuits of prior antioxidant studies in various fields. Emphasis was placed on hydroxybenzene types, particularly substituted hydroquinones. Oxidative stability tests employing the standard A0M procedure and ]]0P shelf storage were used to screen the antioxidants in polyunsaturated oils. The type and number of substituent groups on hydroquinone had considerable effect on antioxidant potency. Some of the experimental compounds, such as 4,4'-methylenebis(5-accnaphthenol) and monoalkylhydroquinones, were several times as effective in the test oils as food-approved antioxidants currently available.