Due to exposure of animals to numerous stress-inducing factors and a high level of cellular metabolism resulting from the conditions and manner in which they are raised, destabilisation of the redox balance towards excessive activity of free radical species is a common phenomenon. Enhancing the antioxidant status of the animal organism by optimising the level and quality of feeding, and especially by supplementation with exogenous antioxidants, may be one essential and highly effective means of improving the health and thus the productivity of animals. Natural plant supplements in diets for poultry can be used to enhance antioxidant defence mechanisms and reduce the intensity of oxidation processes, which negatively affect the quality of poultry products, i.e. meat and eggs. Analysis of the available studies shows that antioxidant processes in the organism of birds can be stimulated via administration of extracted active compounds, among which the highest antioxidant activity is found in resveratrol, hesperidin, genistein, thymol and carvacrol, and herbs, for example from garlic, aloe vera, oregano and rosemary.