The appropriate daily dose of vitamin C is related to the therapeutic purpose and is not a uniform dose. Vitamin C is an essential vitamin and is found in abundance in fruits such as lemons, oranges and green leafy vegetables. Vitamin C tablets can also be taken by healthy people, especially those who lack green leafy vegetables and fruits in their dietary recipes, and it is more appropriate for these people to take 50 to 100 mg of vitamin C per day. When vitamin C is used to treat vitamin C deficiency, it is more appropriate to take 300-600mg of vitamin C per day, divided into three doses. Vitamin C is an acidic drug that can assist the absorption of iron and can be used as an adjunctive treatment for iron deficiency anemia, in which case it is recommended to take 300mg of vitamin C per day, divided into three doses. Prolonged use of large amounts of vitamin C tablets can cause urate, cysteinate or oxalate stones, and overdose can cause diarrhea, red and shiny skin, headache, frequent urination, nausea and vomiting, stomach cramps. It is contraindicated in patients who are allergic to vitamin C components to prevent allergic symptoms such as generalized rashes and itchy skin. It is recommended that patients take vitamin C tablets reasonably under the guidance of a doctor, do not adjust the dose of the drug privately.