1. For those who are poisoned through the mouth: there are burning sensation in the mouth, mucosal erosion and ulceration in the mouth and esophagus, nausea, vomiting, abdominal pain, diarrhea, even vomiting blood, blood in the stool, and even gastric perforation and pancreatitis in serious cases; some patients develop liver enlargement, jaundice and abnormal liver function, and even liver failure. There may be dizziness and headache, and a few patients experience central nervous system symptoms such as hallucinations, fear, convulsions and coma. Kidney injury is the most common, manifested as hematuria, proteinuria, oliguria, elevated blood BUN and Cr, and acute renal failure in severe cases. Lung injury is the most prominent and serious, manifested as cough, chest tightness, shortness of breath, cyanosis, dyspnea, and examination can reveal hypopnea, and dry and wet rales can be heard in both lungs. For those who take large amounts orally, pulmonary edema and pulmonary hemorrhage appear within 24 hours, and often die from ARDS within a few days; those who do not take large amounts have a subacute course, with chest tightness and breath-holding appearing in about 1 week, and dyspnea reaching a peak in 2-3 weeks, and patients often die of respiratory failure. Pneumothorax, mediastinal emphysema, toxic myocarditis, pericardial hemorrhage and other complications occur in a few patients. 2. Local exposure to paraquat poisoning: clinical manifestations are contact dermatitis and chemical burns on mucous membranes, such as skin erythema, blisters, ulcers, etc. Conjunctival and corneal burns form ulcers and even perforations. Long-term exposure to a large number of systemic damage can occur, and even life-threatening. 3.Injecting route (blood vessel, muscle, skin, etc.) exposure to paraquat: Injecting route (blood vessel, muscle, skin, etc.) exposure to paraquat is rare, but the clinical manifestation is dangerous and the prognosis is poor.