Drinking a cup of coffee every day is basically not bad for the body. The caffeine in coffee, when consumed appropriately, can play a role in refreshing the mind, promoting gastrointestinal peristalsis, and increasing the amount of urine, while an excessive amount of it can cause insomnia and other side effects. Coffee’s main efficacy component is caffeine, and some tannin-like substances. The role of caffeine has the following points. 1. Refreshing: Excitement of the nervous system, allowing us to eliminate sleepiness to maintain a certain state of mind, which can improve our work efficiency and thus better work. 2. Promote gastrointestinal peristalsis: promote intestinal peristalsis, especially constipated people drink a little coffee in moderation. 3. Increase the amount of urine: caffeine has a very obvious diuretic effect, can accelerate the turnover of water in the human body, physiological edema people can drink some black coffee moderately. It should be noted that the active ingredients in coffee are limited in dosage and cannot treat or prevent diseases. If you feel panic after drinking coffee, insomnia, diarrhea, etc., it is recommended to drink less or no coffee, if there are corresponding symptoms, or timely medical attention.