Distinguish between preventive and therapeutic use of vitamins Healthy individuals who are already eating a well-balanced diet will not benefit from additional vitamin supplementation. Supplementation may only be necessary for those on a low-calorie (<1200cal/d) diet. Vitamin dosage should be reasonable Excessive dosage may not be easily absorbed in the body and may even be harmful, resulting in adverse reactions/events. Vitamins should not be used as "supplements" to prevent poisoning; the dose of vitamin D, A and cod liver oil for children should be strictly controlled to prevent adverse reactions. Attention to the effects of combined use of drugs 1, long-term application of anti-tuberculosis drugs such as isoniazid, which can lead to a large number of B6 excretion and lack of the body, supplementation of vitamin B6, prevention and treatment of neurological adverse reactions (peripheral neuritis, optic neuritis). 2, anemic children taking vitamin C overdose, promote iron to bivalent iron conversion, improve ferrous sulfate absorption; 3, long-term use of antiplatelet drug aspirin can contribute to the increased excretion of vitamin C, resulting in vitamin C deficiency. 4, long-term or a large number of on the use of endocannabinoids, aminoglycosides, tetracyclines, macrolides, sulfonamides and other antimicrobial drugs can lead to vitamin B, K deficiency. Choose the appropriate time to take Vitamin B2 specific absorption site in the upper part of the small intestine, if taken on an empty stomach is fast gastric emptying, reducing the bio-availability, take after meals.