The general dosage of vitamin C, in the case of adult tablets, is about 100 mg/tablet, and the recommended daily dose is 100-200 mg, one tablet three times a day. If vitamin C is given intravenously, it is also 100-500mg per day for at least a two-week treatment course. For children if taken orally, the recommended dose is 100-300mg per day for a minimum of two weeks. In the case of vitamin C intravenous, also 100-300mg per day for a two week or more treatment course. Vitamin C can have adverse reactions, such as gastrointestinal disorders easily caused by large doses, and large doses can also cause deposition of urates and cysteine salts, as well as adverse reactions such as diabetes and hematological system. If the oral dose is 200-300mg, long-term large oral doses can also cause vitamin C deficiency disease if the drug is suddenly stopped. Excessive use of vitamin C chewable tablets can easily damage tooth enamel, and rapid intravenous administration may also cause dizziness or fainting.