You should not drink milk until at least half an hour after eating grapes. Grapes are rich in vitamin C and phytic acid, and milk is rich in protein, both of which are rich in nutrients. If you drink milk immediately after eating grapes, the phytic acid in grapes will react with the protein in milk, forming indigestible substances that will stimulate the stomach, causing nausea, vomiting, diarrhea, etc., and stomach stones may form when consumed in large quantities. In addition, grapes and milk are both highly irritating to the gastrointestinal tract, and eating them together can lead to excessive secretion of stomach acid. It is recommended to live a regular life, eat more fresh vegetables and fruits, eat a reasonable diet, avoid picky eating, and maintain a balanced nutrition.