The tested tocopherols (gamma, delta, alpha) showed antioxidative activity at all levels of addition to the monounsaturated olive oil, the effects increased as a function of concentrations (maximum: +287% with 800 mg gamma -tocopherol/100 g oil compared to the control oil). In the highly unsaturated linseed oil, which contains 58 mg/100 g initial concentration of gamma -tocopherol, gamma -tocopherol showed antioxidative behavior up to the addition of 100 mg/100 g oil. Additions of more than the 100 mg/100 g affected the oil, resulting in a faster oxidation. Mixtures of gamma/delta -tocopherols in olive oil were found to protect more efficiently than both vitamins when added separately a-tocopherol reduced effects of other tocopherols in both plant oils. The stabilizing effect of added tocopherols and their mixtures (100 mg/100 g oil each) in olive oil are gamma/delta -T>gamma -T>delta -T>gamma/alpha -T>delta/alpha -T>alpha -T and in linseed oil gamma -T>gamma/delta -T>delta -T>gamma/alpha -T>alpha -T>alpha/delta -T.