Preserved eggs, also known as Songhua eggs, change eggs, etc., are processed egg foods invented by Chinese Han people. It is a kind of food unique to China with a special flavor and can promote appetite. According to the "Medical Lin Zhuan Yao", it can "relieve lung heat, sober up alcohol, remove large intestinal fire, and treat diarrhea. It can disperse and condense". It is commonly used to treat sore throat, throat therapy, hoarse voice, and constipation. "