Deaths caused by barbiturate overdoses have increased in the past decade, especially as a result of suicide attempts. Pentobarbitone is a central nervous system depressant used for sedation and euthanasia in veterinary medicine. However, pentobarbitone analysis is not commonly available in the hospital setting; hence, its occurrence in overdoses is under-reported. Herein we describe a patient who ingested pentobarbitone obtained from the Internet with the purpose of ending his life. He became comatose and required ventilation for 6 days. While critically ill, the drug and a barbiturate test kit were found in his room at his residence. Toxicological analysis of the patient\'s blood determined the presence of pentobarbitone at levels of 91, 56, and 19 mg/L at 11, 59, and 107 h after ingestion, respectively. With supportive care, the patient made a full recovery. He stated that he believed the liquid was to be pentobarbitone, and that he had received advice on its use from an online forum that he had found on a dark web marketplace. In this report, we highlight the process by which we facilitated pentobarbitone analysis with a rapid turnaround time, which helped to inform clinical management and raise awareness among clinicians. The access was made through the Prescription, Recreational and Illicit Substance Evaluation (PRISE) programme, which is a collaborative network among the New South Wales (NSW) Ministry of Health, NSW Poisons Information Centre (PIC), and NSW Health Pathology Forensic & Analytical Science Service (FASS).