Four different phenolic fractions from T. officinale leaves and petals were analyzed. All tested fractions from T. officinale leaves and petals had antioxidative properties. They inhibited lipid peroxidation, protein carbonylation and oxidation of protein thiols. Fractions from petals had stronger antioxidant activity than fractions from leaves. Tested dandelion fractions may be a promising source of antioxidants.