Cu Huang Cao can diuretic and remove dampness (promote the operation of water and fluid to expel dampness), activate blood circulation and dissipate blood stasis, stop bleeding and detoxify. Cu Huang Cao is bitter, slightly pungent and cold in nature, and belongs to the liver and kidney meridians. It has the effects of inducing diuresis and removing dampness, activating blood circulation and dispersing blood stasis, stopping bleeding, and detoxifying the toxin. It can be used internally or externally. Catching yellow grass decoction for internal use is commonly used in the treatment of edema, dysuria, jaundice, diarrhea, amenorrhea, metrorrhagia (disorders of the menstrual cycle, excessive vaginal bleeding), as well as bruises, urinary blood, and so on. It should be used with caution for people with cold spleen and stomach. Catch yellow grass is usually used externally as a decoction and wash or mashed compress, and is commonly used in the treatment of canker sores and swollen poisons (localized swelling of the skin, fever, and pain) as well as poisonous snake bites. It is recommended that patients in need of timely medical treatment, under the guidance of a doctor.