Sophora japonica L. is the dried flower bud and flower of Sophora japonica L.Huaimi is mainly produced in Henan, Shandong, Shanxi, Shaanxi, Anhui, Hebei, Jiangsu, Guizhou, and other places. In recent years, Ningxia, Gansu, and other places have scale, Vietnam also has a large area of planting. Flower bud is collected when summer flower is not opened, call pagoda tree rice " Quercetin is extracted from sophora japonica bud. It is soluble in glacial acetic acid, yellow in alkaline solution, almost insoluble in water, and bitter in an alcohol solution. It can be used as a food preservative;  
   1, Quercetin may expel phlegm and arrest coughing, it can also be used as anti-asthmatic.  
   2, Quercetin has anticancer activity, inhibits PI3-kinase activity and slightly inhibits PIP Kinase activity, reduces cancer cell growth via type II estrogen receptors.  
   3, Quercetin may inhibit histamine release from basophils and mast cells.  
   4, Quercetin may control the spread of certain viruses within the body. 5, Quercetin may help reduce tissue destruction.  
   6, Quercetin may also be beneficial in the treatment of dysentery, gout, and psoriasis