Context: Acetylcysteine is an effective treatment for acetaminophen poisoning. The preparation and dose calculation of acetylcysteine is associated with medical errors. The prevalence of this error is 84.3% globally. Case report: A 15-year-old girl took an overdose of acetaminophen in a suicide attempt. Acetylcysteine intravenous was ordered. Due to the medication error by the nurse, she received a 10-fold overdose of intravenous acetylcysteine in both initial loading dose and maintenance dose. On the second day, the patient showed abdominal pain, nausea, vomiting, and elevated liver enzymes. Her hemoglobin, hematocrit, and platelet quickly decreased. Subsequently, she developed oliguria, anuria, and rising serum creatinine levels. The patient was diagnosed with uremic hemolytic syndrome. She underwent hemodialysis and was treated with plasmapheresis, blood transfusions, and platelets. Discussion: The effects of acetaminophen poisoning and acetylcysteine overdose may be much more severe and have a greater impact on patient survival. Timely and accurate treatment measures can help prevent long-term side effects.