Marijuana and its synthetic forms, called synthetic cannabinoids (SCs), are used as recreational drugs. Bonzai is a kind of SC. Adverse cardiovascular events have been reported with abuse of marijuana and SCs, including arrhythmia, myocardial infarction, and sudden cardiac death. Presently described is a case of a 23-year-old, previously healthy man, who was admitted to the emergency department with atrial fibrillation after Bonzai abuse. Sinus rhythm was restored during observation.