Natto itself is not harmful, and if consumed in moderation will not affect your health, but long-term consumption of large quantities may cause indigestion and elevated purine levels in the blood. Natto is a soybean product made from soybean fermented by Natto bacteria, with an average of 16.7g of protein, 11.9g of carbohydrates, 9.2g of fat and other nutrients per 100g of Natto. Natto also contains nattokinase, soy lecithin, unsaturated fatty acids, moderate consumption of cardiovascular benefits. Moderate consumption does not produce harmful substances and is not harmful to health, but if you consume natto in excess for a long period of time, you are prone to indigestion, diarrhea, bloating and other symptoms. In addition, the purine content in natto is relatively high, so it is recommended that gout and high uric acid patients consume it in moderation, and consuming too much may aggravate the condition or trigger gout. As each person has a different degree of digestion and absorption of natto, it is recommended to consume natto in moderation, do not overeat, and those who are allergic to soy should not consume natto.