Calcium carbonate is alkaline. Calcium carbonate dissolved in water hydrolyzes calcium ions and carbonate ions, water decomposes hydrogen ions and hydroxide ions, calcium ions and hydroxide ions combine to form calcium hydroxide, carbonate ions and hydrogen ions combine to form carbonic acid, carbonic acid decomposes to form water and carbon dioxide, calcium hydroxide is alkaline, so calcium carbonate dissolved in water becomes alkaline. Calcium carbonate is generally used as a calcium supplement and antacid. It is used for the prevention and treatment of calcium deficiency, and is available for children, pregnant and lactating women, menopausal women, and the elderly, especially patients with osteoporosis, osteogenesis imperfecta, and rickets. Calcium carbonate in the supplementation of human calcium at the same time, there will be some adverse reactions need to be observed. 1. Calcium carbonate often causes belching (hiccups) and constipation after taking it. 2. Milk-alkali syndrome may occasionally occur in some people, manifested by hypercalcemia, renal dysfunction and alkalosis. 3. Long-term use of large quantities may cause a rebound increase in gastric acid secretion or hypercalcemia. When taking calcium carbonate for calcium supplementation treatment, the following aspects need to be noted. 1. Use with caution for people with cardiac and renal insufficiency. 2. Those who are allergic to this product should not use it, and those with allergies should use it with caution under the guidance of a doctor. 3. Prohibit the use of this product when its properties have changed. 4. Avoid accidental ingestion by children when placing this product. 5. Minors must be used under adult supervision. 6. If you are using other drugs, please consult your physician or pharmacist before using this product. 7. Patients with kidney stones should use it under the supervision of a physician. If any discomfort occurs while taking it, you should go to the hospital in time to avoid missing the best treatment time.