Although there are many advantages to knocking sunflower seeds, we should not knock sunflower seeds excessively. To think of the other side of the problem, knocking sunflower seeds also has disadvantages, that is, knocking sunflower seeds will consume a lot of saliva. Saliva has some more important functions besides moistening the oral mouthpiece for vocalization and food swallowing. Modern medical research has found that saliva contains substances that promote hemostasis and contraction of blood vessels, which can speed up blood coagulation, reduce wound bleeding and promote wound healing. Saliva can neutralize the acid produced by bacteria in the mouth, protect teeth and prevent dental caries. Saliva contains secretory immunoglobulin A and lysozyme, which has immune and antibacterial effects. Saliva contains digestive enzymes, which can turn polysaccharides into disaccharides for human body to absorb; In addition, saliva is an anticancer agent, which can reduce the toxicity of carcinogens such as aflatoxin and benzopyrene. Saliva also contains salivary hormones, which have a certain influence on the development of bones and teeth, calcium and phosphorus metabolism in blood, and protein synthesis. Therefore, people who eat sunflower seeds in large quantities and consume saliva in large quantities are prone to diseases such as aphtha, tongue sore, dental caries, gingivitis and mumps. In addition, because sunflower seeds are often unclean, it is easy to spread diseases such as hepatitis and dysentery. This point cannot but arouse people's attention.