Vitamin D and vitamins A, E and K are fat-soluble vitamins, which are suitable to be taken after meals, usually best taken about half an hour after meals in the morning and evening to facilitate the body’s absorption. Vitamin D is a fat-soluble vitamin that can prevent rickets and is usually abundant in fish, liver, cream and egg yolk. The human skin is exposed to sunlight, in which seven dehydrocholesterol can also be transformed into vitamin D3, which is effective for adolescents in the growth period and the elderly who are prone to osteoporosis. Adults can generally get vitamin D supplements through a normal diet. However, attention needs to be paid to the presence of underlying gastric diseases, such as gastric ulcer and erosion, and it is best to take it half an hour after a meal to avoid damaging the gastric mucosa. Vitamin D can also cause adverse reactions, such as cardiac arrhythmia, convulsions, increased nocturia, etc., which can mostly resolve on their own. In addition, cardiac insufficiency, arteriosclerosis, and pregnant and lactating women should be used with caution.