The analysis of dynamic changes in the metabolome of plants of the genus Euphorbia (E. palustris and E. squamosa) from the Helioscopia section was fulfilled. Using chromatography-mass spectrometry analysis with subsequent statistical processing of the metabolite matrix, a significant part of the metabolomic changes occurring in the process of changing the phenological phases of plant was revealed. A single vegetative organ of a plant may reflect systemic changes in the metabolome of the organism. The inter-species differences of plants appear differently depending on the stage of development.