1, Paraquat is more toxic, can be absorbed through the skin, digestive tract and respiratory tract to cause acute poisoning, more often caused by oral aqueous solution, is the herbicide that causes the most deaths from acute poisoning in humans, oral lethal dose of 2-4 grams, oral 20% concentration of the liquid 10 ml can be reached to the lethal dose. It has multi-system damage to human, especially the most serious damage to lungs. 2.It is mainly accumulated in the lungs after absorption, absorbed by alveolar type I and type II cells, and activated as free radicals in the cells, causing lung damage, free radicals can also cause extensive damage to other systems, but also cause serious local damage to the skin, mucous membranes and so on. 3, Paraquat poisoning has no specific treatment. Poisoned persons should be quickly and thoroughly cleaned and detoxified: 1) vomiting; 2) gastric lavage can be 30% white clay, slurry water or activated charcoal, can be served with laxatives; 3) blood perfusion as soon as possible. 4, drug treatment: high-dose corticosteroid plus cyclophosphamide; antioxidant and free radical scavenger (SOD, VitC), cardiac glycosides, VitB1 and so on. 5, paraquat poisoning early should avoid the use of oxygen, never available high concentration of oxygen, such as respiratory distress, cyanosis, partial pressure of oxygen is less than 40mmHg can only be used greater than 21% oxygen inhalation. In conclusion, paraquat poisoning first aid treatment is relatively tricky, at present there is still a lack of effective way to reduce the mortality rate of the treatment, to pay attention to the early diagnosis and treatment of acute paraquat poisoning.