Cat hair grass can drink on an empty stomach. Generally, Chinese medicines for invigorating qi and nourishing blood can be taken on an empty stomach. Drugs that help digestion and strengthen the stomach are recommended to be taken after meals. Cat hair grass, also known as Hypericum japonicum, Eupatorium adenophorum and Eupatorium adenophorum, is a monocotyledonous plant of Gramineae with sweet, light and cool nature. Can be used for adjuvant treatment of common cold and fever, infantile fever, wet dream's nocturnal emission, turbid urine, short and red urine, stranguria, heat stranguria, hepatitis jaundice, urethritis, diabetes, etc. It has the effects of cooling and dissipating heat, diuresis and stranguria, and clearing away heat and jaundice.