[Diquat poisoning leads to ARDS: report of two cases].

Diquat (DQ) is a non-selective, foliage-applied herbicide that is known to cause liver and kidney damage, while the impact on the lungs is relatively mild. Current domestic and international reports on diquat poisoning primarily focus on liver and kidney injuries, with limited documentation of cases leading to acute respiratory distress syndrome (ARDS) and lung damage. This paper presents a retrospective analysis of two documented cases of diquat poisoning, both exhibiting ARDS. In both cases, the condition rapidly progressed upon the onset of ARDS despite aggressive treatment, ultimately resulting in the death of the patients.

Two cases of diquat poisoning in adolescent children.

Diquat (DQ) is among the most widely used herbicides, and its intake can cause severe systemic toxicity that manifests rapidly. The resultant symptoms can cause the dysfunction of a range of tissues and organs,. As there is no specific antidote for diquat poisoning and the efficacy of extant treatments is suboptimal, physicians must acquire a more comprehensive understanding of the most effective approaches to managing affected patients. Relative few studies have been published to date focused on diquat poisoning in pediatric patients. In this report, we compare two similar cases of juvenile diquat poisoning with dynamic changes in clinical manifestations, laboratory values, and imaging results. For the first time, the difference in whether to perform blood flow perfusion and the time difference of initiation of hemoperfusion had a clear clinical difference in the subsequent effects of diquat poisoning in children with diquat poisoning. Limited evidence is available regarding the efficacy of early hemoperfusion for diquat poisoning; however, the differences in clinical outcomes articulated here highlight the benefits of early and timely hemoperfusion therapy in the treatment of DQ toxicity in children, in conjunction with primary supportive care in the management of DQ poisoning in children.

Simultaneous determination of diquat, paraquat, glufosinate, and glyphosate in plasma by liquid chromatography/tandem mass spectrometry: from method development to clinical application.

Diquat (DQ), paraquat (PQ), glufosinate (GLU), and glyphosate (GLYP) are commonly used herbicides that have been confirmed to be toxic to humans. Rapid and accurate measurements of these toxicants in clinical practice are beneficial for the correct diagnosis and timely treatment of herbicide-poisoned patients. The present study aimed to establish an efficient, convenient, and reliable method to achieve the simultaneous quantification of DQ, PQ, GLU, and GLYP in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS) without using derivatization or ion-pairing reagents. DQ, PQ, GLU, and GLYP were extracted by the rapid protein precipitation and liquid-liquid extraction method and then separated and detected by LC-MS/MS. Subsequently, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, extraction recovery, matrix effect, dilution integrity, and stability were evaluated to validate the method based on the FDA criteria. Finally, the validated method was applied to real plasma samples collected from 166 Chinese patients with herbicide poisoning. The results showed satisfactory linearity with low LOD (1 ng/mL for DQ and PQ, 5 ng/mL for GLU, and 10 ng/mL for GLYP, respectively) and low LOQ (5 ng/mL for DQ and PQ, 25 ng/mL for GLU and GLYP, respectively). In addition, the precision, accuracy, extraction recovery, and stability of the method were acceptable. The matrix effect was not observed in the analyzed samples. Moreover, the developed method was successfully applied to determine the target compounds in real plasma samples. These data provided reliable evidence for the application of this LC-MS/MS method for clinical poisoning detection.

[Effects and significance of continuous hemoperfusion on patients with diquat poisoning].

OBJECTIVE: To investigate the effect of continuous hemoperfusion (HP) on the levels of soluble CD14 isoform (sCD14-st) and neutrophil gelatinase-associated lipocalin (NGAL) on patients with diquat (DQ) poisoning and its significance. METHODS: A total of 86 patients with acute DQ poisoning admitted to the department of emergency medicine, Harrison International Peace Hospital Affiliated to Hebei Medical University from May 2018 to August 2021 were enrolled and divided into the intermittent HP group (40 cases) and the continuous HP group (46 cases) according to the random number table method. All patients received basic treatment and continuous veno-venous hemofiltration (CVVH) within 24 hours after admission. On this basis, the intermittent HP group received HP treatment within 2 hours, lasting 2 hours each time for every 8 hours, 3 times in all; the continuous HP group received continued HP treatment until there was no DQ component in urine samples. Serum NGAL levels were detected in all patients before treatment and at 3 hours, 12 hours, 24 hours, 2 days, 3 days, 5 days, and 7 days after treatment. At the same time, serum sCD14-st, blood lactate (Lac), arterial partial pressure of oxygen (PaO2), serum creatinine (SCr), MB isoenzyme of creatine kinase (CK-MB) and interleukin-18 (IL-18) levels were detected before treatment and at 24 hours, 3 days, and 7 days after treatment. Kaplan-Meier survival curve was drawn to analyze the 28-day survival of patients. RESULTS: Before treatment, there was no significant difference in serum NGAL, sCD14-st, Lac, PaO2, SCr, CK-MB and IL-18 levels between the two groups. With the prolongation of treatment, the serum levels of NGAL, sCD14-st, Lac, SCr, CK-MB and IL-18 in the intermittent HP group increased at first and then decreased. Serum levels of NGAL, sCD14-st, CK-MB and IL-18 reached their peaks at 24 hours after treatment, and the Lac and SCr levels reached their peaks at 3 days after treatment. In addition, the levels of the above indexes at each time point in the continuous HP group were all significantly lower than those in the intermittent HP group [after 24 hours of treatment: NGAL (µg/L) was 345.90±30.75 vs. 404.24±38.79, sCD14-st (ng/L) was 1 941.88±298.02 vs. 2 656.35±347.93, CK-MB (U/L) was 30.67±9.11 vs. 43.28±8.06, IL-18 (ng/L) was 139.49±16.29 vs. 177.98±27.85; 3 days of treatment: Lac (mmol/L) was 2.98±0.26 vs. 3.72±0.49, SCr (µmol/L) was 125.01±24.24 vs. 156.74±28.88; all P < 0.05]. However, there was no significant difference in PaO2 levels between the two groups at each time point after treatment. The Kaplan-Meier survival curve showed that the 28-day mortality of patients in the continuous HP group was significantly lower than that in the intermittent HP group [26.09% (12/46) vs. 52.50% (21/40); Log-Rank test: χ 2 = 7.288, P = 0.007]. CONCLUSIONS: Continuous HP could effectively reduce serum sCD14-st, NGAL levels and 28-day mortality in patients with DQ poisoning, with good curative effect.

Identification of differentially expressed genes and pathways in diquat and paraquat poisoning using bioinformatics analysis.

OBJECTIVE: In this study, differentially expressed genes (DEGs) and signaling pathways involved in diquat (DQ) and paraquat (PQ) poisoning were identified via bioinformatics analysis, in order to inform the development of novel clinical treatments. METHODS: Raw data from GSE153959 were downloaded from the Gene Expression Omnibus database. DEGs of the DQ vs. control (CON) and PQ vs. CON comparison groups were identified using R, and DEGs shared by the two groups were identified using TBtools. Subsequently, the shared DEGs were searched in the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, using the Database for Annotation, Visualization, and Integrated Discovery. A protein-protein interaction (PPI) network was constructed, and hub genes were identified using the cytoHubba plug-in in Cytoscape software. Finally, circos and contrast plots showing the DEGs shared between mouse and human chromosomes were constructed using TBtools. RESULTS: Thirty-one DEGs shared by the DQ and PQ groups were identified. Enriched biological process terms included positive regulation of cell proliferation and translation. Enriched cellular component terms included extracellular region, intracellular membrane-bounded organelle and mitochondrion. Enriched molecular function terms included transcription factor activity and sequence-specific double-stranded DNA binding. Enriched KEGG pathways included the interleukin-17 signaling pathway, tumor necrosis factor signaling pathway, and human T-cell leukemia virus 1 infection. The top 10 hub genes in the PPI network were prostaglandin-endoperoxide synthase 2 (Ptgs2), chemokine (C-X-C motif) ligand 2 (Cxcl2), colony-stimulating factor 2 (granulocyte-macrophage) (Csf2), matrix metallopeptidase 13 (Mmp13), amphiregulin (Areg), plasminogen activator, urokinase receptor (Plaur), fos-like antigen 1 (Fosl1), epiregulin (Ereg), activating transcription factor 3 (Atf3), and transferrin receptor (Tfrc). Cxcl2, Csf2, and Atf3 played important roles in the mitogen-activated protein kinase (MAPK) signaling pathway. CONCLUSIONS: These pathways and DEGs may serve as targets for gene therapy.

Simultaneous determination of paraquat and diquat in human plasma by HPLC-DAD: Its application in acute poisoning patients induced by these two herbicides.

BACKGROUND: Paraquat and diquat are widely used in agricultural production in many countries, which are very toxic to human beings. Paraquat can be detected in some diquat solution sold in the market. The blood concentration of paraquat or diquat is an important indicator for clinical diagnosis of paraquat or diquat poisoning. So, it is very meaningful to develop a method for simultaneous determination of paraquat and diquat in human plasma. OBJECTIVE: To develop and validate a HPLC-DAD method for simultaneous determination of paraquat and diquat in human plasma and to apply it in the acute poisoning patients by these two herbicides. METHODS: Paraquat and diquat were simultaneously determined by HPLC-DAD. The plasma was treated using Waters OASIS® Column and then separated on a Thermo Hypersil GOLD (250 × 4.6 mm, 5 µm) Column with the mobile phase consisted of 75 mmol/L sodium heptane sulfonate (containing 0.1 mol/L phosphoric acid, pH 3.0) and acetonitrile (87:13, v:v) at a flow rate of 1.0 mL/min. The full-wavelength scanning was 200-400 nm, and the detection wavelength of paraquat and diquat was 257nm and 310nm, respectively. 120 and 30 plasma samples from patients with paraquat and diquat poisoning were collected and analyzed by the established method. RESULTS: The standard curve for paraquat and diquat ranged from 0.05 to 20 µg/mL, and the precision of LLOQ for paraquat was 16.49%, which was required to be less than 20%. The precision of other concentrations was less than 14.14%. The recovery of paraquat and diquat was 95.38%-103.97% and 94.79%-98.40%, respectively. The results showed that paraquat and diquat were stable under various storage conditions. 120 plasma samples of paraquat poisoning patients and 30 plasma samples of diquat poisoning patients were determined by the established method. The blood concentration of paraquat ranged from 0.10 to 20.62 µg/mL, with an average of 3.61 µg/mL, while for diquat, the concentration ranged from 0 to 26.59 µg/mL, with an average of 2.00 µg/mL. Among the diquat suspected poisoning samples, 5 samples were detected not only diquat but also paraquat, and 2 samples were detected only paraquat, no diquat. CONCLUSION: The HPLC-DAD method established in this study was high throughput, high sensitivity, simple operation, and wide linear ranges. It can be used for the screening analysis and quantitative detection of paraquat and diquat in acute poisoning patients, which can provide basis for the treatment and prognosis of these two herbicides poisoning patients.

[Simultaneous determination of paraquat and diquat in plasma and urine by ion chromatography-triple quadrupole mass spectrometry].

Paraquat (PQ) and diquat (DQ) are widely used as non-selective contact herbicides. Several cases involving accidents, suicide, and homicide by PQ or DQ poisoning have been reported. Poising by PQ, which is mainly concentrated in the lungs, causes acute respiratory distress syndrome and leads to multiple organ toxicity. The toxic effects of DQ are similar to those of PQ but relatively less intense. The mortality rates in PQ and DQ poisoning are high. Simultaneous monitoring of the PQ and DQ concentrations in plasma and urine can provide valuable information for early clinical diagnosis and prognosis. High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is the main analytical method used to detect PQ and DQ in plasma and urine. As both these compounds are highly polar and water soluble, they cannot be retained effectively on a reversed-phase column with conventional mobile phases. The separation of PQ and DQ by ion-pair chromatography or hydrophilic chromatography has been reported. The use of an ion-pairing reagent helps in improving the retention capabilities of PQ and DQ. However, the sensitivity of MS detection is noticeably decreased because of ion suppression caused by the ion-pairing reagent in the mobile phase; furthermore, ion-pairing reagents may contaminate the MS system. The separation of PQ and DQ by hydrophilic chromatography is easily affected by matrix components in the sample, and their retention times are not stable. Considering PQ and DQ are bicharged cation species in solution, they are more suitable for separation by cation-exchange chromatography. A method based on ion chromatography-triple quadrupole mass spectrometry was established for the determination of PQ and DQ in plasma and urine. The plasma and urine samples were diluted with water, and then purified on a solid-phase extraction column containing a polymer-reversed phase and weak ion-exchange mixed-mode adsorbent (Oasis WCX). PQ and DQ were separated on an IonPac CS 18 analytical column (250 mm×2.0 mm, 6.0 µm) with gradient elution using a methylsulfonic acid solution electrolytically generated from an on-line eluent generation cartridge. An in-line suppressor was used to remove methylsulfonate and other anions from the eluent before the eluent entered the mass spectrometer. Between the suppressor and the ion source in MS, the addition of 3% (v/v) formic acid in acetonitrile as an organic modifier (using an auxiliary pump and a T-piece) aided desolvation in the ion source, resulted in a one-or two-fold improvement of the response, and eliminated the residual effects of the adsorption of PQ and DQ caused by ion source. The analytes were detected by triple quadrupole tandem mass spectrometry using positive electrospray ionization in the multiple reaction monitoring (MRM) mode. PQ-d8 and DQ-d4 were used as internal standards. The calibration curves for PQ and DQ showed good linear relationships in the ranges of 1.0-150 µg/L and 0.5-75 µg/L, respectively, and the correlation coefficients were > 0.999. The average matrix effects of PQ and DQ in plasma were 84.2%-89.3% and 84.7%-91.1%, while the average matrix effects of PQ and DQ in urine were 50.3%-58.4% and 51.9%-59.4%. The average recoveries of PQ and DQ in plasma were 93.5%-117% and 91.7%-112%, respectively, with relative standard deviations (RSDs) of 3.4-16.7% and 2.8%-13.2%, and that in urine were 90.0%-118% and 99.2%-116%, with relative standard deviations of 5.6%-14.9% and 2.4%-17.3% (n=6). The limits of detection of PQ and DQ in plasma and urine were 0.3 µg/L and 0.2 µg/L, respectively, with the corresponding limits of quantification being 1.0 µg/L and 0.5 µg/L. This method is sensitive and accurate, and it can be used to determine PQ and DQ for clinical diagnosis and prognosis in patients.

Fabrication of benzenesulfonic acid groups modified magnetic microspheres as an MSPE adsorbent for fast determination of paraquat and diquat in human urine combined with UPLC-HRMS.

In this study, novel benzenesulfonic acid groups modified magnetic microspheres (Fe3O4@SiO2@poly(4-VB)) were synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectrometry (FTIR), and vibrating sample magnetometer (VSM). The as-prepared Fe3O4@SiO2@poly(4-VB) was employed as a magnetic-phase extraction (MSPE) adsorbent for rapid determination of paraquat (PQ) and diquat (DQ) in human urine samples coupled with ultra-high performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). Moreover, this paper had expounded systematically the mass spectrum cracking mechanisms of PQ and DQ. And a zwitterionic functionalized SIELC Obelisc R column was employed for separation and retention of the above two polar herbicides using 50 mmol/L ammonium formate (pH = 3.7)-acetonitrile as the mobile phase. Besides, the adsorption and desorption conditions of Fe3O4@SiO2@poly(4-VB) toward PQ and DQ were optimized in spiking urine samples to obtain the best adsorption and desorption efficiencies. And the adsorption mechanisms of Fe3O4@SiO2@poly(4-VB) toward PQ and DQ referred to synergetic effect of electrostatic attraction and π-π interaction. Under the optimal conditions, the inter-day and intra-day spiking recoveries of the proposed method were in the range of 86.7-109.9% with RSDs less than 10%. The limits of detection (LODs) were obtained by spiking in blank urine samples at a series of low concentrations and were found to be 0.12 µg/L and 0.14 µg/L for PQ and DQ, respectively, which were lower than the comparing literatures. The developed analytical method was proven to be simple, rapid, sensitive, and accurate for clinical poisoning analysis.

Successful extracorporeal membrane oxygenation support for severe acute diquat and glyphosate poisoning: A case report.

RATIONALE: Because of the lack of an antidote or effective treatment, patients with severe acute diquat and glyphosate poisoning always died within a few hours. Extracorporeal membrane pulmonary oxygenation (ECMO), as an artificial heart-lung supporting system, can be applied to support lung that is expected to recover from reversible pathological damage. However, to our knowledge, the application of ECMO for patients with diquat and glyphosate poisoning has not been reported. PATIENT CONCERNS: A 40-year-old man ingested in 100 ml of diquat (20 g/100 ml) and 400 ml glyphosate (41 g/100 ml) was admitted to the intensive care unit (ICU), immediately complicated by the development of ventricular fibrillation, respiratory failure, renal failure, and multi-organ failure. DIAGNOSIS: Diquat and glyphosate poisoning were diagnosed by stated ingestion history, and the diagnostic criteria for acute respiratory distress syndrome (ARDS) and multi-organ dysfunction syndrome were also met. INTERVENTIONS: He was treated with veno-venous ECMO. OUTCOMES: He was successfully transferred out of the ICU on day 46 and discharged on day 67. The computed tomography scan showed no obvious pulmonary fibrosis 2 months after poisoning. LESSONS: ECMO may be effective in the treatment of patients with severe ARDS caused by diquat and glyphosate poisoning when conventional management does not work.

Human and experimental toxicology of diquat poisoning: Toxicokinetics, mechanisms of toxicity, clinical features, and treatment.

Diquat (1,1'-ethylene-2,2'-bipyridinium ion; DQ) is a nonselective quick-acting herbicide, which is used as contact and preharvest desiccant to control terrestrial and aquatic vegetation. Several cases of human poisoning were reported worldwide mainly due to intentional ingestion of the liquid formulations. Its toxic potential results from its ability to produce reactive oxygen and nitrogen species through redox cycling processes that can lead to oxidative stress and potentially cell death. Kidney is the main target organ due to DQ toxicokinetics and redox cycling. There is no antidote against DQ intoxications, and the efficacy of treatments currently applied is still unsatisfactory. The aim of this work was to review the most relevant human and experimental findings related to DQ, characterizing its chemistry, activity as herbicide, mechanisms of toxicity, consequences of poisoning, and potential therapeutic approaches taking into account previous experience in developing antidotes for paraquat, a more toxic bipyridinium herbicide.

Intoxicação por diquat / Diquat intoxication

O paraquat e o diquat são herbicidas de contacto do grupo dos bipiridilos, utilizados largamente para controlo de ervas daninhas. A importância deste grupo de herbicidas reside na sua utilização frequente para fins suicidas e pela inexistência de antídoto ou tratamento médico específico. O envenenamento com diquat é muito menos comum que com o paraquat e por isso existem poucos casos descritos na literatura. A dose letal de ambos é sobreponível, contudo o diquat é considerado menos tóxico devido ao menor dano pulmonar. Por outro lado, o diquat tem efeitos tóxicos graves sobre o sistema nervoso central. Por este motivo os sinais de neurotoxicidade pelo diquat são os mais relevantes e incluem sinais de parkinsonismo. O rim é a principal via excretora do diquat e a necrose tubular aguda é a lesão tipicamente identificada. A sobrevida depende de dois fatores: a concentração da substância no plasma e o tempo após a ingestão. O tratamento centra-se em três pontos essenciais: prevenção da absorção, rápida excreção e modificação dos efeitos tecidulares. A hemoperfusão é mais eficaz na clearance do diquat do que a hemodiálise e a sua utilização nas primeiras 12 horas de intoxicação pode reduzir a mortalidade.

Paraquat and diquat are contact herbicides from bipyridyl group, commonly used in weed control. The importance of this herbicide group is due to its frequent use with suicidal purpose and because there is neither an antidote nor a specific treatment. Poisoning with diquat is much less common that with paraquat, so there are few cases published in literature. The lethal dose of both is similar, however diquat is considered less toxic because it causes less lung damage. On the other side, diquat has severe toxic effects on central nervous system and neurotoxic signs are the more relevant, and include Parkinsonism. The kidney is the main excretory pathway of diquat and acute tubular necrosis is typical. Survival depends on two factors: plasma concentration and time of ingestion. Treatment focus in three key points: preventing absorption, rapid excretion and tissue effects. Hemoperfusion is more effective in diquat clearance than haemodialysis and its use in first 12 hours can reduce mortality.

Magnitude and characteristics of acute paraquat- and diquat-related illnesses in the US: 1998-2013.

BACKGROUND: Paraquat and diquat are among the most commonly used herbicides in the world. OBJECTIVES: Determine the magnitude, characteristics, and root causes for acute paraquat- and diquat-related illnesses in the US METHODS: Illnesses associated with paraquat or diquat exposure occurring from 1998 through 2011 were identified from the Sentinel Event Notification System for Occupational Risks (SENSOR)-Pesticides Program, the California Department of Pesticide Regulation (CDPR) Pesticide Illness Surveillance Program (PISP), and the Incident Data System (IDS). Cases identified by the National Poison Data System (NPDS) were reviewed for the years 1998-2003 and 2006-2013. RESULTS: A total of 300 paraquat- and 144 diquat-related acute illnesses were identified by SENSOR, PISP, and IDS. NPDS identified 693 paraquat- and 2128 diquat-related acute illnesses. In SENSOR/PISP/IDS, illnesses were commonly low severity (paraquat=41%; diquat=81%); however, SENSOR/PISP/IDS identified 24 deaths caused by paraquat and 5 deaths associated with diquat. Nineteen paraquat-related deaths were due to ingestion, seven of which were unintentional, often due to improper storage in beverage bottles. In SENSOR/PISP/IDS, paraquat and diquat-related acute illnesses were work-related in 68% (n=203) and 29% (n=42) of cases, respectively. When herbicide application site was known, the vast majority of acute paraquat-related illnesses (81%) arose from agricultural applications. Common root causes of illness were failure to use adequate personal protective equipment (PPE), application equipment failure, and spill/splash of herbicide. CONCLUSIONS: Although the magnitude of acute paraquat/diquat-related illnesses was relatively low, several fatalities were identified. Many illnesses could be prevented through stricter compliance with label requirements (e.g. ensuring proper herbicide storage and PPE use), and through enhanced training of certified applicators.

The poison pen: bedside diagnosis of urinary diquat.

Diquat is a bipyridyl herbicide with nephrotoxic effects. This in vitro study demonstrates a colorimetric test for detection of diquat in human urine. Urine specimens using ten concentrations of diquat herbicide solution and controls for urine and glyphosate were prepared. A two-step assay (addition of bicarbonate followed by sodium dithionite) was performed, with a resulting color change of the original solution for each specimen. Color change intensity was noted immediately and after 30 min, by gross visual inspection. A green color with concentration-dependent intensity was detected in all specimens, in which concentrations of diquat solution ranged from 0.73 to 730 mg/L. This colorimetric effect disappeared after 30 min. The sodium bicarbonate/dithionite test may be useful as a qualitative bedside technique for the detection of urinary diquat in the appropriate clinical setting.

Fatal diquat intoxication.

BACKGROUND: Since the introduction of diquat in agriculture practice in 1960's, about 40 cases of poisoning have been described in detail in medical literature. CASE REPORT: We presented two cases. A case one, a 35-year-old, previously healthy, woman ingested 14% diquat solution. The poisoning had fulminant course, consisted of severe stomachache, vomiting, cardiocirculatory shock, respiratory failure and cardiac arrest 20 hours post-ingestion. Autopsy revealed myocardial infarction, bronchopneumonia and incipient renal damage. A case two, a 64-year-old man developed severe gastroenteritis, corrosive lesions of mucosal surfaces, acute renal injury, arrhythmias, brain stem infarction and bronchopneumonia. The diagnosis of diquat poisoning was made retrospectively upon the clinical picture and identification of pesticides he had been exposed to. The patient died 18 days post-exposure. The most prominent findings on autopsy were pontine hemorrhage and infarction, bronchopneumonia, left ventricle papillary muscle infarction and renal tubular damage. CONCLUSION: Cardiocirculatory disturbances led to fatal complications, the heart and brain infarction. We pointed out the heart as one of the most severely affected organs in diquat poisoning.

Rapid analysis method for paraquat and diquat in the serum using ion-pair high-performance liquid chromatography.

In the present study, by using IPCC-MS3 (GL Sciences Inc. Tokyo, Japan) as the counter-ion in the mobile phase, we established a simple, quick method of analysis that separated and quantified paraquat and diquat on an ODS column by introducing the deproteinized serum sample directly into HPLC. The calibration curve of paraquat and diquat detected at UV 290 nm showed good linearity when the concentration of the injected sample was in the range 0.1-10.0 microg/ml. The detection limit was 0.05 microg/ml, and the mean recoveries (n=5) added 1.0 microg/ml each of paraquat and diquat to standard serum were 87.5% and 89.1%, respectively, while the RSD were 4.52% and 3.85%. All of these were good results, and the time taken for one analysis was less than 30 min. As a result of employing this analytical method for the analyses in four cases of acute poisoning, it was possible to decide promptly on treatment approaches for all of the present cases.