The purpose of this work is to identify the phenolic compounds of the marigold inflorescences, as well as the quantitative determination of flavonoids in the extraction obtained by extracting inflorescences with 40% ethanol.Earlier, with the purpose of preliminary assessment and subsequent selection of the fraction obtained by treating the feed with ethyl alcohol of different concentrations, the total content of antioxidants in alcohol-aqueous extracts from the inflorescences of marigolds was studied. In parallel, pharmacological screening confirmed that the most pronounced antioxidant, wound-healing and endothelioprotective activity is extracted, the alcohol obtained by ethanol 40%.In this paper, the results of the phenol composition of the most pharmacologically active fraction obtained by extracting ethyl alcohol 40% of marigolds spread out are presented. The raw materials – the inflorescences of marigolds of the propagated varieties "Carmen" were collected in September 2016 in the botanical garden of the Pyatigorsk Medical and Pharmaceutical Institute, a branch of of FGBOU in VolgGMU Ministry of Health of Russia.In the analyzed extract, 4 substances of polyphenol nature – patuletin, patulintrin, quercetin and caffeic acid – were identified. Analytical characteristics of substances were determined by physicochemical methods.Using UV spectrophotometry using the value of the specific absorption index, the quantitative content of the sum of flavonoids in terms of patuletin is determined and is 2,98 ± 0,06%. The methodology is validated by such indicators as specificity, linearity, accuracy, precision.