Objective:To explore the clinical value of "hydration therapy" in the treatment of severe acute paraquat poisoning (APP).Methods:A prospective historical control observation was conducted. Fifty-eight patients with severe APP admitted to Shouguang People's Hospital Affiliated to Weifang Medical College from February 2014 to June 2019 were enrolled. Twenty-six patients admitted before May 10th, 2016 were enrolled in the standard treatment group. After being admitted to intensive care unit (ICU) from the department of emergency, patients in the standard treatment group were immediately given standard treatment such as repeated gastric lavage, catharsis, adsorption of poison by activated carbon or montmorillonite powder, drug treatment and blood purification. From May 10th, 2016, 32 patients were enrolled in the intensive treatment group. On the basis of standard treatment, "hydration therapy" was carried out, that was, 0.9% NaCl and/or 5% glucose injection were used for continuous intravenous infusion throughout the day, so as to ensure that the total amount of fluid infusion per day reached 200 mL/kg within 48-72 hours after ICU admission. At the same time, furosemide was used to strengthen diuresis to ensure the balance of water and electrolyte. If heart failure or acute pulmonary interstitial edema occurred during the treatment, "hydration therapy" should be stopped immediately. Six months after treatment, all patients were followed up. The patients with normal activity, no complaints of discomfort and no damage of heart, lung, liver, kidney and other organs were regarded as cured. The therapeutic effect of "hydration therapy" was evaluated.Results:There was no significant difference in gender, age, dosage or time from taking poison to ICU between the two groups. In the intensive treatment group, 32 patients did not appear heart failure during continuous rehydration treatment. Follow-up after 6 months showed that the overall cure rate in the intensive treatment group was significantly higher than that in the standard treatment group [59.4% (19/32) vs. 19.2% (5/26), P < 0.05]. In the 6-month follow-up, there was no significant difference in age or time from taking poison to ICU between the two groups, but the dosage in the intensive treatment group was significantly higher than that in the standard treatment group (mL: 54.06±26.03 vs. 23.00±4.47, P < 0.05). After 6 months of follow-up, chest CT showed that the lesions of pulmonary fibrosis of cured patients in both group gradually reduced with time, not completely progressive and irreversible. Conclusion:"Hydration therapy" with intensive diuresis can significantly improve the rescue success rate of patients with severe APP.