Caffeine (1,3,7-trimethylxantine), a structural analog of adenosine, is widely used as a central nervous system stimulant in beverages and drugs. Caffeine overdose induces hypokalemia, fatal ventricular fibrillation, and cardiac arrest, resulting in death. We describe a case of caffeine overdose that presented with refractory ventricular fibrillation that was treated with supportive care because invasive care for severely ill patients was limited due to the COVID-19 pandemic. A 20-year-old woman with no underlying medical history ingested 90,200-mg caffeine tablets (total dose 18 g) in a suicide attempt. She was transported to the emergency department 45 min after ingestion with dizziness, palpitations, nausea, and vomiting. She developed cardiac arrest 80 min after ingesting the caffeine, with refractory ventricular tachycardia that recurred for about 2.5 h. Advanced life support including defibrillation was started immediately and we gave intravenous Intralipid emulsion, potassium chloride, amiodarone, and esmolol, without hemodialysis or extracorporeal membrane oxygenation (ECMO). The ventricular fibrillation was stopped 4 h after ingestion. As supportive care, mechanical ventilation, sedatives, and neuromuscular blockade were continued until 12 h after ingestion. Although she suffered from prolonged, refractory ventricular tachycardia, she recovered without complications. This case report describes the clinical course of severe caffeine intoxication without an active elimination method, such as hemodialysis or ECMO and explores the treatment of caffeine intoxication with a literature review.