Common chicory (Cichorium intybus L.) is a promising source of raw materials for both food (roots) and pharmaceutical industries (leaves). One of the ways to increase the biologically active compounds content in medicinal plant materials is the use of various growth stimulants, which include amino acids. The article presents the results of an experimental study conducted in 2021-2022 which study the effect of of L-alanine and a racemic mixture of alanine (DL) on the accumulation and qualitative composition of phenolic compounds (PC) in the leaves of chicory.Results. It was found that the use of alanine in different concentrations did not have a significant effect on the increase of phenolic compounds content, and also did not affect the on their accumulation dynamics. The use of alanine enantiomers did not affect the qualitative composition of phenolic compounds, but led to a change in the ratio of hydroxycinnamic acids to each other. It has been established that during the growing season the percentage ratio between the main phenolic compounds in chicory leaves changes - the content of chlorogenic acid increases in proportion to the decrease in chicory acid. Treatment with L-alanine at a concentration of 25 mg/l during the study period in both varieties led to the largest reduction in the content of chicory acid compared to others. It was noted that the total content of PC is higher in a year with warmer and more arid weather, it was higher on average by 0,7 %.