Introduction.- The aim of this paper is to underline the need for systematic monitoring of patients treated with anticholinergic antipsychotic drugs. We present the clinical history of a 34-year-old adult, treated with quetiapine in combination with other drugs with anticholinergic effects. Case report.- A 34-year-old male adult had been suffering from bipolar disorder since 2001. He was treated with risperidone, but he was not compliant due to adverse effects, including decreased libido and erectile dysfunction. On June 5th 2012, it was decided to administrate 600 mg per day of quetiapine in combination with tropatepine consequent to an episode of agitation and aggressiveness. On June 14th 2012, while the patient was receiving diazepam and valproic acid, loxapine oral solution was introduced. On June 23th, the patient started mentioning digestive disorders, such as diffuse abdominal pain with constipation but continued to pass gaz. On June 25th, at 6:30 am, he declared abdominal pain, which worsened at 8:15 am despite administration of analgesics, followed by malaise and onset of vomiting. His laboratory tests showed leukocytosis 11.2 G/L with neutrophils 7.7 GA.. The abdomen's radiograph without preparation showed small bowel and colonic air-fluid levels. The result of the CT scan confirmed an occlusive syndrome affecting the whole small gut and colon. At 1 pm, the patient's condition worsened. He received an intramuscular injection of 100 mg of loxapine and an opioid treatment, including tramadol and morphine. At 2:30 pm, the clinical condition further deteriorated with an onset of generalized abdominal contracture, the absence of abdominal breathing, sweating, tachycardia at 104 beats per minute, and hypothermia of 34.5 degrees C. He was transferred to an intensive care unit. Laboratory tests showed metabolic acidosis, elevated liver enzymes and acute renal failure. He received volume expansion and was treated by renal replacement therapy and antibiotics. He was intubated and transferred to the operating room. At laparotomy, both colonic necrosis with perforation and necrosis of the small bowel were seen. The patient underwent total colectomy with small bowel resection, distal ileostomy and closure of the rectal stump. The onset of septic and hemorrhagic state required further surgery on June 26th. The evolution was characterized by multi-organ failure with acute anuric renal failure, multiple cardiac arrests, and systemic bacterial and fungal infection. On July 24th, this unfavorable outcome lead to death. In summary, the patient had an occlusive syndrome due to neuroleptics and complications, including mesenteric ischemia with necrotizing colitis. Discussion/conclusion.- Quetiapine, like all antipsychotics, has anticholinergic effects, including cardiac, psychiatric and digestive disorders. The combination of anticholinergic drugs decreases intestinal peristalsis. Without any prompt management, this decrease can result in a colonic ischemia or necrosis. In patients treated with neuroleptics, the onset of constipation must alert medical staff. Systematic monitoring of bowel movements should be performed in any patient receiving anticholinergic drugs. (C) 2016 L'Encephale, Paris.