Patients diagnosed with acute paraquat poisoning in the Emergency Room of the First Affiliated Hospital of Zhengzhou University would be stratified according to disease severity and randomly assigned to four different groups: HD, HP, HP-HD and control (conservative therapy) group for different treatment. Arterial blood gas test, complete blood count, coagulation function, liver function, pancreatic function, urine dithionite test, renal function and chest radiographs would be closely monitored during treatment. Primary endpoint is 60-day mortality. Secondary endpoints include survival time, rate of multiple organ failure, rate of mechanical ventilation, in-hospital length of stay, etc.