Grapes contain a lot of vitamins, minerals, dietary fiber, phytochemicals and other nutrients, which are useful for improving immunity, relieving constipation and replenishing blood sugar. However, due to the high sugar content and cold taste of grapes, excessive consumption may cause dental disease, gastrointestinal disorders, and increased blood sugar, it is recommended to eat in moderation, not more than 300 grams per day. The following symptoms may occur if you eat too many grapes: 1. Dental disease: grapes contain a lot of fermented sugar substances, which may cause corrosive effects on the teeth and lead to tooth decay. In addition, grapes are acidic, so too much of them may stimulate the gums, causing sour and soft teeth and weak chewing. The amount of food should be controlled, especially for infants, the elderly and patients with poor gastrointestinal function; 3, elevated blood sugar: grapes are high sugar fruits, too much consumption may cause elevated blood sugar, diabetes and obese patients should be cautious.