Antioxidative activity of carotenoid preparations obtained from tomato, paprika and of (β-carotene against free radicals, in the linoleic acid autoxidation process and in lipoxygenase-catalysed enzymatic reaction were investigated in the study. Better properties of β-carotene comparing to other preparations were stated. β-Carotene applied in the 15 mg% concentration exhibited 100% activity against free radicals and completely inhibited the linoleic acid autoxidation process and enzymatic oxidation catalysed by lipoxygenase. Tomato carotenoids preparation showed not much worse properties towards free radicals and in the autoxidation process, whereas paprika carotenoids preparation had distinctly lower activities. All the investigated carotenoids inhibited the formation of the secondary oxidation products the weakest (tomato preparation up to 10% and β-carotene up to 30%) and paprika preparation exhibited prooxidative tendencies in higher concentrations. The change of the enzymatic reaction system from continuous to emulsified caused a distinct improvement of the preparation’s activity.