Mercury is harmful to the human central nervous system, digestive system, urinary system, respiratory system and skin mucosa. 1. Mercury on the human central nervous system will produce certain hazards, neurasthenia, memory deterioration, poor sleep quality, emotional instability, dizziness, headache, ataxia, speech impediment, numbness of the limbs, limb activity is not conducive to, or even paralysis, and so on. 2. If mercury enters the human body through the digestive tract inadvertently, gastrointestinal symptoms such as nausea, vomiting, diarrhea, abdominal pain, etc., and may even cause acute liver function damage. 3. Renal excretion is one of the main ways for mercury to enter the human body, so it may damage the renal tubules and glomeruli, and may even lead to acute renal failure. 4. When mercury enters through the respiratory tract, respiratory irritation symptoms such as coughing, sputum, dyspnea, etc. may occur, and even interstitial pneumonia and acute respiratory failure may occur. 5. Mercury contact with human skin and mucous membrane will also produce certain harm, resulting in skin and mucous membrane damage, skin pigmentation, etc.. People who have been exposed to mercury should seek medical attention when the above symptoms occur.