The invention discloses a method for extracting high-purity asarinin and use thereof. The method comprises: putting crude asarum powder in an SFE-CO2 device； under the conditions that an extraction kettle has a pressure of 30-40 Mpa and a temperature of 45-70° C., separating kettles I and II have a pressure of 5-10 Mpa, a temperature of 30-50° C. and the flow rate of CO2 is 35-60 L/h, extracting for 60-240 min to obtain total volatile oil of asarum； standing the total volatile oil of asarum for 24-72 h at a low temperature, and carrying out suction filtration under reduced pressure to obtain crude asarinin； and re-crystallizing the crude asarinin in absolute ethanol twice to obtain pure asarinin. It is found for the first time that asarinin has a good cough-relieving activity and thus can be used in preparing medicines for treating various types of coughs.
