The main reason why silver fungus stewed for a long time causes cancer is because long time stewing causes nitrite to be produced within the silver fungus soup, which has a certain risk of causing cancer. Therefore, when making silver fungus soup, just cook it and avoid stewing it for a long time. Silver fungus soup is sweet and contains many amino acids, polysaccharides, vitamins, fiber and minerals such as iron, calcium and phosphorus, all of which are beneficial to human health. However, prolonged stewing of silver fungus will destroy the nutrients and cause nutrient loss, thus reducing the edible value of silver fungus soup. If stewed for a long time, it may produce nitrite, which is toxic. If stewed for a long time, it may increase the risk of cancer, leading to higher risk of esophageal cancer, stomach cancer and other diseases, and it may also affect the hematopoietic function of the body. In addition, the stomach contains nitrate-reducing bacteria, and the nitrite in the long-stewed silver fungus soup is combined with amines under the action of nitrate-reducing bacteria to form amine nitrite, which also increases the risk of cancer. Therefore, it is important not to stew silver fungus soup for a long time. In addition, it is important not to consume damp, moldy or deteriorated fungus, and to avoid soaking fungus for a long time. If silver fungus stew needs to be kept overnight, it should be refrigerated and should not exceed two days, otherwise it is easily contaminated by pathogenic bacteria to produce rice fermentation bacterium acid, which is harmful to human body and can cause abdominal pain, diarrhea and other adverse reactions, resulting in digestive system disorders.