Diarrhea after drinking black coffee is usually related to drinking on an empty stomach, allergies, history of gastrointestinal disease, drinking too much or unclean coffee. In daily life, try to drink warm water, mainly for gastrointestinal health. Drinking black coffee diarrhea analysis has the following points: 1, fasting: drinking coffee on an empty stomach, caffeine stimulates gastrointestinal peristalsis to accelerate, while coffee will stimulate gastric acid secretion, affecting the digestive function of the stomach, which leads to diarrhea. Drinking coffee on an empty stomach stimulates the gastrointestinal tract and is very likely to damage the stomach function, causing gastric ulcers, stomach cramps and other diseases. Therefore, you should try to avoid drinking coffee on an empty stomach; 2, allergic: patients are allergic, the organism is allergic to caffeine, and the symptoms of diarrhea will occur after drinking coffee. Such patients should try to avoid drinking coffee; 3, gastrointestinal history: patients with previous history of chronic gastritis, enteritis, gastric ulcer, duodenal ulcer and other diseases, after drinking black coffee, will stimulate gastric acid secretion, promote gastrointestinal peristalsis, symptoms of diarrhea; 4, drinking unclean or unseasoned: if black coffee is not preserved in an appropriate manner, or preserved for too long, it may deteriorate, and after drinking due to cause acute gastritis. leading to diarrhea. In addition, such as drinking too much coffee, the patient’s own gastrointestinal sensitivity, after drinking coffee will promote intestinal peristalsis, accelerate digestion, will play a role in defecation, too much coffee will stimulate the stomach, which may lead to diarrhea. Generally speaking, after drinking black coffee diarrhea belongs to the phenomenon of stress, during this period you can take montelukast to control the symptoms of diarrhea, while paying attention to diet generally the next day diarrhea symptoms will be relieved, if the symptoms continue for 2-4 days without relief, this is the earliest possible hospital visit to investigate the causes.