Vitamin C is a water-soluble vitamin, it is recommended to take it between meals to be able to achieve the best absorption effect and maximum bioavailability, it is recommended to take it after breakfast and before lunch, which is at 9-10 am, this time period is relatively good. The next time to take it after lunch and before dinner, which is 17-19 pm, this time period is also relatively good, to achieve the maximum degree of drug absorption. However, the above-mentioned taking time is exceptional for a patient who has had previous gastric diseases, such as active ulcers, gastroduodenal ulcers or previous esophagogastric fundic varices, upper gastrointestinal bleeding, such patients are recommended to take vitamin C within 15-30 minutes after meals to avoid stimulation of the gastrointestinal tract.