Drinking coffee in moderation has no obvious harmful effects on the body, but drinking large amounts of coffee may lead to increased nervous excitement, gastrointestinal discomfort and calcium loss. 1. Increased nerve excitability: When drinking large quantities of coffee, the caffeine in coffee can cause excessive nerve excitability, which can lead to insomnia, headache, mental instability and other discomforts. 2. Gastrointestinal reaction: coffee contains more caffeine, ellagic acid, etc., when drinking a large amount of coffee can lead to gastric discomfort, especially if the patient himself suffers from underlying gastric diseases, such as gastric ulcer, gastritis, gastroesophageal reflux patients, prone to abdominal pain, abdominal distension, acid reflux, belching (hiccups) and other symptoms. 3. Calcium loss: The caffeine in coffee has a diuretic effect. If a large amount of coffee is ingested so that the caffeine content reaches a certain level, it can cause a large amount of calcium in the blood to be lost with the exudation of urine. In the long run, it will increase the incidence of osteoporosis. It is recommended that coffee be consumed in moderation in life, 200 to 300 milliliters of black coffee per day is sufficient, not excessive. Especially after menopause, women should limit the intake of coffee, children, pregnant women and breastfeeding women are not recommended to drink coffee.