Patients with poor gastric function, especially those with excessive gastric acid secretion, should try not to drink black coffee. Poor gastric function is often manifested by epigastric distension, early satiety, anorexia, nausea and vomiting, and acid reflux. Acid reflux patients due to excessive secretion of gastric acid, accompanied by the upper esophageal sphincter relaxation, such patients should be prohibited from drinking coffee. If the gastric acid secretion is insufficient to cause indigestion and bloating patients can drink less coffee. Caffeine, the main component of coffee, when absorbed by the body, will stimulate the secretion of gastric acid, relax the sphincter at the lower end of the esophagus, aggravate the symptoms of acid reflux and heartburn, and also improve the symptoms of indigestion. Even so, patients with too little gastric acid secretion should drink less coffee to reduce the burden on the stomach and intestines. And those who have obvious symptoms of digestive discomfort should seek medical attention in time to avoid delaying their condition.