The dried rhizomes and roots of the plant, Willow-leaved Plant, or Coriander-leaved Plant. Chinese medicine believes that Bai Qian taste pungent, bitter, slightly warm, the main return to the lung meridian, with the lungs to lower the qi, expectorant cough effect. This product is good at lowering the qi, qi lowering will be phlegm, cough and asthma since the cessation, for the lung family cough and asthma medicine. It can be used in combination regardless of heat or cold. It is mostly used for coughing with phlegm and dampness in the lung, coughing with excessive phlegm and chest fullness and wheezing. When used clinically for wind-cold cough, it can be used in combination with roasted ephedra and almonds. When used for phlegm-dampness congestion of the lung and cough with excessive phlegm, it can be used in combination with Radix et Rhizoma Halcyonii, Chen Pi and Ginger. When used for chronic bronchial asthma, it can be used with roasted Ephedra and Su Zi. When used for chronic bronchial asthma combined with infection and fever, it can be taken with Sangbai Pi, Shengdi, Dioscorea, Poria, Roasted Ephedra and Ginger in a decoction, such as Baiqian Tang.