A 34-year-old man reported heart fluttering and near syncope a few hours after marijuana smoking. In the emergency department, he was found to have a right bundle-branch-type ventricular tachycardia. The patient underwent a successful electric cardioversion. Coronary angiography showed no pericardial artery stenosis yet very slow coronary blood flow. Clinical tachycardia was also inducible in the electrophysiologic laboratory. After verapamil therapy and cessation of marijuana, his coronary flow normalized and ventricular tachycardia was no longer inducible in the electrophysiologic laboratory. Marijuana use might affect coronary microcirculation and cause ventricular tachycardia. Verapamil therapy and cessation of smoking might be curative.