The objective of the research study was to assess the contents of vitamin C, polyphenols, and carotenoids, and to determine the antioxidant properties of industrially produced powders from selected plant materials using a freeze-drying method followed by micronisation. Twelve  powders were analyzed: fruit & vegetable powders, nettle powder and barley grass powder; all of them enjoy a growing consumer  interest. The contents of vitamin C, various polyphenol fractions, and carotenoids were determined by a highperformance liquid  chromatography (HPLC) and the antioxidant properties by a spectrophotometric method using synthetic ABTS^·+ cation radicals. Depending on the type of plant materials analyzed, the powders produced were characterized by a diversified, rather high content of bioactive substances tested and by the antioxidant activity. The highest content of vitamin C was found in powders from sea buckthorn  and kale fruits (333 and 348 mg / 100 g, respectively) and in powders from a mixture of red fruits and vegetables (486 mg / 100 g). The  chokeberry and blueberry powders were characterized by the highest content of total polyphenols and the highest antioxidant activity. Based on the research results obtained, it was found that, depending on the nature of the powders produced, they can be applied to make  functional food, food for particular nutritional uses, and dietary supplements; those powders can be applied not only for their sensory  qualities but, also, because they contain valuable constituents: natural vitamin C, polyphenols, and carotenoids.