Introduction Epidural infusion of local anesthetics with opioids is widely used for pain control during the perioperative—and peripartum—periods. Selection of the opioid, appropriate dosing, and follow‐up by the acute pain service are critical in providing safe postoperative epidural analgesia. Case Report Summary A 71‐year‐old man was scheduled for a parastomal hernia repair with midline laparotomy. The parastomal hernia was a complication from a previously performed colectomy for ulcerative colitis. Preoperatively, the patient received a lower thoracic epidural catheter. The epidural infusate (0.2% ropivacaine with 0.5 µg/mL sufentanil) was prepared and double‐checked by holding area nurses. The fact that the right prescription medication label partially covered a morphine label went unnoticed. The intraoperative phase was characterized by stable parameters. Postoperatively, it was not possible to demonstrate an epidural nerve block. No pain was reported, and the patient could be transferred to the ward. The patient developed coma and delayed respiratory depression after discharge to the surgical ward, requiring intensive care unit admission and naloxone administration. Analysis of the syringe content revealed the presence of morphine (1 mg/mL). Discussion Color‐coded prefilled syringes combined with the use of an epidural specific syringe connector to prevent cross‐connections should become standard practice. In addition, delayed respiratory depression should be considered after epidural administration of morphine.