To prevent and control orthopedic diseases, many people take calcium tablets for calcium. If calcium tablets are taken on an empty stomach or while eating soy or dairy products, they may irritate the stomach. Calcium tablets taken orally need to be broken down into calcium ions by the action of gastric acid in order to be fully absorbed and utilized. The secretion of gastric acid depends mainly on the timing of meals, and taking calcium supplements during or after a meal is more conducive to calcium absorption. In addition, calcium ions will also promote the secretion of stomach acid, and taking calcium tablets on an empty stomach will easily cause excessive stomach acid and discomfort. Alkaline calcium supplements (such as calcium carbonate, etc.) can also play a role in neutralizing stomach acid and can reduce the stimulation of stomach acid on the gastric mucosa when taken after a meal. Therefore, it is recommended that you do not take calcium supplements on an empty stomach. Calcium supplements are best taken in small amounts several times a day, at or after three meals. Since calcium absorption is at its peak at night, it is most effective when taken after dinner. Within 2 hours before and after taking calcium tablets, you should try to avoid eating foods containing more oxalic acid such as spinach, green peppers and cilantro, as well as drinking coffee, tea, juice and carbonated or alcoholic beverages, otherwise the calcium will be easily absorbed and may form stones. Similarly, foods high in fiber (such as celery, coarse grains) and foods with too much fat will also affect the absorption of calcium. Most notably, calcium tablets are best not eaten with soy and dairy products. 1, because calcium and they are easy to clump, affecting the digestion and absorption function of the stomach, causing belching, indigestion and other symptoms. 2, may cause “milk – alkaline syndrome”, manifested as high blood calcium, alkalosis and kidney function damage. 3, iron and zinc will also affect the absorption of calcium, it is best to take calcium tablets after more than 3 hours before taking drugs containing these two ingredients.