A study has been made on the effects of the dietary administration of a selection of volatile oils from medicinal plants on the polyunsaturated fatty acid composition in the retina of aged (28 month old) rats. Polyunsaturated fatty acids comprised by far the major proportion of the total unsaturated content within the retinal phospholipids with docosahexaenoic acid predominating. The administration daily of 3-9 mg of the essential oils from clove, nutmeg, pepper and thyme over a period of 17 months resulted in the maintenance of very much higher levels of polyunsaturated fatty acids, in particular docosahexaenoic acid, within the retinal phospholipids. This increase occurred mainly at the expense of a reduction in the level of oleic acid. The possible efficacy for the application of the oils from such medicinal plants through their antioxidant capacities in the prevention of age-related macular degeneration is discussed.