Introduction <p>Acute organophosphorus insecticide poisoning is a significant cause of self-poisoning suicides and deaths due to unintentional exposure. Although atropine combined with pralidoxime is the standard treatment foracute organophosphorus poisoning, its effectiveness in reducing mortality remains uncertain.</p> Objective <p>This study aimed to conduct a meta-analysis on the therapeutic effects of addingmagnesium sulphate to the standard treatment for acute organophosphorus poisoning.</p> Methods <p>We systematically searched clinical studies on PubMed, MEDLINE, Embase and Cochrane databases from their inceptionuntil June 2024. Additionally, we performed citation analysis to identify both published and unpublished studies on the therapeutic effect of addingmagnesium sulphate to the standard treatment for acute organophosphorus poisoning, focusing on mortality and the need for intubation. We utilized RevMan Web 2023 to conduct the meta-analysis using Mantel-Haenszel method. For randomized controlled trials (RCTs), outcomes were pooled as risk ratios (RR) with 95% confidence intervals (CI), while for observational studies, outcomes were pooled as odds ratios (OR) with 95% CI. Statistical heterogeneity was assessed using the I² statistic. A random effects model was employed if the I² value was 50% or higher; otherwise, a fixed effects model was used. The confidence in effect estimates was evaluated based on the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The protocol for this systematic review is registered in PROSPERO (registration number: CRD42022310934).</p> Results <p>Our meta-analysis included seven randomized controlled trials with sample sizes ranging from 40 to 100 patients, and five observational studies with sample sizes ranging from 15 to 133 patients. Most of the studies exhibited significant methodological biases.</p> <p>For RCT studies, the mean (SD) age of 247 patients who received add-on magnesium sulfate with standard treatment for acute organophosphorus poisoning was 31.9(8.4) years, while the mean (SD) age of 217 patients who received only the standard treatment was 34.7(12.8) years. Patients receiving add-on magnesium sulfate had 63% significantly lower mortality rate compared to the standard treatment group [RR (95% CI) = 0.37 (0.21-0.65), I² =12%] and a 27% significantly lower intubation rate compared to the standard treatment group [RR (95% CI) = 0.73 (0.59-0.91), I² = 0%]. For observational studies, patients receiving an additional 4g of magnesium sulfate did not reduce mortality rate compared to the standard treatment group [OR (95% CI) = 0.49 (0.23-1.01), I² = 0%].</p> Conclusion <p>Magnesium sulfate when used as an add-on treatment to atropine and pralidoxime can significantly reduce mortality and intubation rates in patients with acute organophosphate poisoning. The limitation of this meta-analysis is the poor quality and small sample sizes of the included studies, highlighting the need for larger, high-quality multicenter randomized trials to better understand the role of magnesium sulfate in treating organophosphorus poisoning.</p>