Authentic purple-flowered bitter herbs can only be found in Guannan, Jiangsu. "Yanzi Chunqiu·Zaxia No. 10" says: "When I heard it: Oranges grown in Huainan are called oranges, and those grown in the north of Huaibei are called tangerines. They are similar, but the taste is different. "The same goes for bitter vegetables, which are available all over the country. Jiangsu Guannan purple bitter vegetables are the most authentic. When using them, add brown sugar instead of irritating things like ginger. There is also a need to pay attention when picking, so you cannot use fake purple bitter herbs casually. Eating fake ones will outweigh the gains and will be harmful to your health. It is particularly important to identify purple bitter herbs, so be careful.