Long-term moderate amount of coffee, generally does not cause significant harm to the body, but if a large number of long-term coffee or espresso, can easily lead to insomnia, gastrointestinal discomfort, rapid heartbeat and so on. 1. Insomnia: coffee contains a large amount of caffeine, this substance has the role of excitation of the brain and nervous system, a small amount of drink can be invigorated, but if a large number of long-term drink, it is easy to lead to insomnia, especially before going to bed can not drink. 2. Gastrointestinal discomfort: drinking large quantities of coffee for a long time will cause some stimulation of the gastric mucosa, resulting in excessive secretion of gastric acid, thus causing gastric discomfort. 3. Rapid heartbeat: If the intake of caffeine is too much, it will easily lead to tachycardia, and some patients may experience arrhythmia due to their sensitivity. It is recommended to drink coffee in moderation, not long-term excessive drinking, to avoid adverse effects on the body.