The article presents results of the study of a comparative analysis of essential oil obtained from fresh and dried leaves of medicinal sage (Salvia officinalis L.), growing in the Botanical Garden of the First Moscow State Medical University named after Sechenov. The studies were carried out using gas chromatography– mass spectrometry. Qualitative and quantitative difference in the component composition of the essential oil obtained from fresh and dried raw materials was determined as a result of the study.