Cannabis is a frequently used recreational drug that potentially imposes serious health problems. We report three cases where recent and/or chronic use of marijuana led to severe cardiac dysfunction. All three patients collapsed at home and required cardiopulmonary resuscitation (CPR) with initial restoration of spontaneous circulation (ROSC). The mechanism of the cardiovascular collapse was different in each case. The first case presented with asystole and was found to have diffuse coronary vasospasm on coronary angiography in the hours after acute cannabis abuse. In the second case, an acute anterior infarction with occlusion of both the right coronary artery (RCA) and the left anterior descendens (LAD) was observed in a young patient without known cardiovascular risks but with chronic cannabis abuse. The third case presented at home with ventricular fibrillation presumably caused by an acute coronary syndrome due to left anterior descending (LAD) artery occlusion. The hetero-anamnesis of the family reported that all three patients had recently used cannabis. Toxicological screening also showed no other substance abuse than cannabis. Using these three cases, we would like to illustrate that the widespread use of cannabis is not as innocent as is believed. Cannabis use can lead to severe cardiovascular problems and sudden death, not only in people at increased cardiovascular risk, but also in young people without any medical history or risk factors.