The antioxidants such as polyphenols, especially flavonols, present in large quantitites in cocoa, cause vasodilation, modulate inflammatory markers and cardiovascular health, and possess a range of protective cardiovascular effects. On the other hand, overconsumption of chocolate can lead to tachyarrhythmias, supraventricular tachycardia, atrial fibrillation, ventricular tachycardia and ventricular fibrillation due to its caffeine content. This review describes both the cardioprotective and adverse effects of chocolate and its constituents.