Caffeine is a relatively common substance in additives nowadays and is more abundant in coffee. If you accidentally take too much caffeine orally, you will experience anxiety, agitation, excitement, dizziness, headache and other neurological symptoms. Caffeine allergy can also cause cardiovascular symptoms, more commonly various rapid arrhythmias, and some people will experience increased heart rate and redness in the face while drinking coffee. Caffeine not only affects the nervous system and cardiovascular system, but also stimulates the gastrointestinal tract during oral intake, resulting in gastrointestinal symptoms such as nausea and vomiting. If the patient himself has a history of gastric ulcer or gastric mucosal lesions, there is a risk of aggravating the gastrointestinal disorder and stomach bleeding. There can also be symptoms of the skin system, which are relatively rare and commonly seen as hives. For poisoning with large amounts of caffeine, it is recommended to go to the emergency department at the earliest for the purging of the digestive tract, mainly for the treatment of emetic, gastric lavage and catheterization.