The following paper considers aspects of systematic and ecological structure of the weed medicinal plants growing in the biosphere reserve Pribuzhskoye Polesye. The studied weed plants of the region are considered to be used in pharmacology and medicine. Therefore, a detailed study of environmental groups and economic importance of commensal medicinal plants can serve as a basis for new trends development in resource studies of medicinal plants. The paper identifies diagnostic signs, as well as similarities and differences of morphometric evidence. The collection of field data was carried out by reconnaissance of the terrain. The study shows that the territory of the biosphere reserve Pribuzhskoye Polesye is characterized by a rich species composition of synanthropic weed medicinal plants of 57 species growing in different habitats that can be used for the treatment of diseases of the gastrointestinal tract, circulatory system and respiratory system. It is necessary to use weed plants for medicinal purposes to increase the base of receiving biologically active materials of plants.