A method and associated system of treating a plant material consisting essentially of the plant cannabis in order to extract cannabinoids in liquid form from the plant material. The method includes heating the plant material; drying the plant material; grinding the dried plant material into a powder form; marinating the dried plant powder in a solvent for a predetermined time period to form a marinated mixture; shaking and heating the marinated mixture; filtering the mixture so that only a liquid part of the mixture remains; and evaporating from the liquid the solvent in order to provide the cannabinoid liquid extract.