The aim of this study was the evaluation of antioxidative properties of coenzyme Q₁₀, phytosterols and glutathione, represented as inhibition of formation of secondary oxidation products as a result of oxidation of fatty acids – present in sunflower oil which is emulsified in typical food products conditions. The tested substances were added in concentration 5 mg%, the oxidation was catalyzed by Fe(II) ions addition at 37ºC. Evaluation of the main oxidation secondary product (hexanal) occurrence was performed using gas chromatography coupled with mass spectrometry (GC-MS) after headspace solid phase microextraction of volatile compounds (HS-SPME). Moreover, the isolation of phytosterols from plant oils deodorization distillate was carried and characterization of the phytosterols mixture was done using GC-MS. The prooxidant activity of glutathione (up to -105%) and phytosterols (up to -41%) was observed, whereas coenzyme Q₁₀ up to third day of emulsion oxidation acted as antioxidant (up to 18%), but from 7th day acted as prooxidant (up to – 41%). The antioxidant activity (up to 33%) of combination: coenzyme Q₁₀, phytosterols and glutathione was observed, therefore there can be assumed that synergetic effect occurred. The increase rate of hexanal quantity during oxidation period for all the emulsions was similar, only in emulsion with coenzyme Q₁₀ its faster formation was observed.