Natto is more appropriate to eat about 30 to 50g a day, and can be eaten with meals. Natto has a high nutritional value, containing 19.26% protein, as well as nattokinase, fat, amino acids, edible fiber, saponins, isoflavones, calcium, iron, potassium and other minerals. It is generally recommended to eat 30 to 50g a day to meet the body’s needs, so as not to eat more will increase the metabolic burden on the kidneys. And more recommended to eat natto at mealtime, can increase the feeling of satiety, but also to improve digestion and protein digestion utilization. It should be noted that peptic ulcer, acute gastritis, chronic superficial gastritis patients should not eat more natto, at the same time nephritis, renal failure, renal dialysis patients should not eat natto, suffering from gout or uric acid in the body is too high should not eat a large number of natto, gastrointestinal tract wounds have not healed after the operation should not eat natto. If the consumption of natto appeared after the symptoms of discomfort, it is recommended that timely medical treatment, allergic to soy foods should not eat natto.