Caffeine has the hazards of promoting sympathetic excitation, over-activation of the central nervous system, addiction, irritation of the gastrointestinal mucosa, pain, etc., as follows:1. Promote sympathetic excitation: it can make the heart beat faster, induce chest tightness, chest pain, and rapid arrhythmia; 2. Over-activation of the central nervous system: it makes people feel restless, headache, causes or aggravates insomnia, increases tension, anxiety, and induces potential Mental illness, serious patients will experience disorientation, limb convulsions, and even death; 3, addictive: once use is stopped, dizziness, headache, drowsiness, irritability, and symptoms such as inattention, lack of energy, yawning; 4, stimulation of the gastrointestinal mucosa: can cause nausea, vomiting, loss of appetite, diarrhea and other gastrointestinal symptoms; 5, pain: frequent, high-dose use of caffeine It can also cause chronic back pain.