BACKGROUND Mad honey intoxication occurs after ingestion of honey containing grayanotoxin. CASE REPORT We report the case of a 36-year-old man who ingested mad honey and developed atrial fibrillation. DISCUSSION Mad honey intoxication is often characterized by symptoms such as hypotension, bradycardia, and syncope. Patients may also experience gastrointestinal, neurologic, and cardiovascular symptoms due to intoxication. Cardiac rhythm abnormalities, including sinus bradycardia, atrioventricular blocks, and nodal rhythms, also may be observed. To our knowledge, this is the first case report of a 36-year old man developing atrial fibrillation with a slow ventricular response after mad honey ingestion.