1例47岁女性患者为次日行肠镜检查做肠道准备，给予复方聚乙二醇电解质散（Ⅲ）4袋（73.59 g/袋）溶于4 L温水中分16次服用。患者2 h内服用2 L含药温水，用药后1 h内出现稀便和水样便共10余次。因腹泻严重，患者未再继续服用药物。用药后14 h患者出现神情淡漠，呼之不应，双上肢不自主活动，16 h后出现意识丧失伴四肢强直性抽搐。实验室检查示血清钠120 mmol/L，血浆渗透压258.22 mOsm。诊断：低钠性脑病。患者除聚乙二醇电解质散（Ⅲ）外未服用其他药物，考虑低钠性脑病与该药有关。立即给予补钠、脱水等对症治疗。治疗1 h后，患者意识恢复；8 h后复查，血钠142 mmol/L。“,”A 47-year-old female patient received compound polyethylene glycol electrolytes powder (III) 4 bags (73.59 g/bag) dissolved in 4 L warm water in 16 divided doses to prepare for colonoscopy the next day. The patient took medicated warm water 2 L within 2 hours. She had loose stool and watery stool for more than 10 times within 1 hour after medication. The patient did not continue to take drugs because of the severe diarrhea. Fourteen hours after medication, the patient developed apathy, no response to voice stimuli, and involuntary movement of both upper limbs. Sixteen hours after medication, the patient developed unconsciousness and tetanic convulsion of limbs. Laboratory tests showed that serum sodium was 120 mmol/L and plasma osmolality was 258.22 mOsm. She was diagnosed with hyponatremia encephalopathy. Except polyethylene glycol electrolytes powder (III), the patient did not take any other drug. It was considered that hyponatremia encephalopathy was related to polyethylene glycol electrolytes powder (III). Symptomatic treatments such as sodium supplement and dehydration were given immediately. After 1 hour of treatment, the patient′s consciousness recovered; 8 hours later, her serum sodium was 142 mmol/L.