Black coffee can stimulate the gastric mucosa. Coffee contains tannic acid substances, the stimulation of the stomach is relatively large, can lead to an increase in gastric acid, there is also some damage to the mucosa, long-term stimulation may lead to gastritis, gastric ulcer and reflux esophagitis and other diseases. Coffee contains caffeine can promote sympathetic nerve excitation, accelerate gastric peristalsis, promote gastric acid secretion, has produced gastric acid may also stimulate the generation of more gastric acid, can aggravate the patient’s original gastrointestinal tract diseases caused by abdominal pain, abdominal distension and other symptoms, or lead to recurrent episodes. If the patient has an upset stomach or is concerned about the impact on gastrointestinal function, he or she may not consume coffee or may reduce the amount of coffee he or she consumes, or at least should not consume it on an empty stomach. If any discomfort occurs, it is recommended to go to a regular hospital in a timely manner, after clarifying the cause of the disease, under the guidance of the doctor to carry out targeted treatment.