A 17-year-old previously healthy boy (height: 170 cm, weight: 65 kg) visited a local hospital 1 h after ingesting ~200 mL diquat (20 g/100 mL). Gastric lavage and 2 h of hemoperfusion were performed. Methylprednisolone (200 mg), pantoprazole (40 mg twice a day), reduced glutathione (2.4 g), furosemide (20 mg, intravenous, twice a day), and mannitol were administered as cathartics. Nine hours after ingestion, he developed restlessness and oliguria. Sixteen hours after ingestion, he was transferred to our department during which he developed chest tightness. Physical examination revealed impaired consciousness, with a Glasgow coma scale score of 12 (E4V3M5). His vital signs were as follows: heart rate, 168 beats/min; blood pressure, 167/108 mmHg; respiratory rate, 42 breaths/min, and oxygen saturation, 97%. Physical examination revealed no other abnormalities despite abdominal distention and weakening of abdominal sounds; his urine color based on the sodium bicarbonate/dithionite test was dark green (Figures 1A,B). His blood diquat concentration was 4.9 mug/mL. His creatinine (400 mumol/L), urea (11.7 mmol/L), and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations were elevated, but his total bilirubin (TBIL) concentration was normal; his CK and myohemoglobin (MYO) concentrations were 2,534 IU/L and 4,425 ng/mL, respectively. His blood beta2-microglobulin (12.7 mg/L, normal value 0.7-1.8 mg/L), urine beta2-microglobulin (165 mg/L, normal value <0.22 mg/L), and urine microalbumin (3,040 mg/L, normal value <30 mg/L) concentrations were elevated. Computed tomography (CT) revealed partial intestinal gas and dilatation at the fluid level (Figures 1C,D) as well as diffuse cerebral edema. Endotracheal intubation and hemoperfusion (HA330, Jafron, China, 2 h/treatment) were performed. Treatment included midazolam, disoprofol, esmolol, betamethasone (8 mg), pantoprazole (40 mg, twice a day), reduced glutathione (2.4 g), alanyl glutamine (20 g), and furosemide (80 mg twice a day). Twenty hours after ingestion, the patient was anuric after hemoperfusion; his blood diquat concentration was 3.4 mug/mL. Continuous veno-venous hemofiltration (CVVH; Prismaflex ST100, Gambro, Sweden) was immediately performed. After 8 h of CVVH, his blood diquat concentration decreased to 1.5 mug/mL. The patient experienced progressive anuria and abdominal distension. Repeated hemoperfusion and subsequent continuous veno-venous hemodiafiltration (CVVHDF; Prismaflex ST100) were performed. The patient then developed respiratory failure caused by pulmonary edema, and mechanical ventilation was performed. The patient died 40.5 h after diquat ingestion owing to refractory circulatory collapse and progressive hypoxemia. The patient's main laboratory tests results were shown in Table 1 (Case 1).