answer:No. It can cause irregular heartbeat: “Larger doses of caffeine, especially when given to non-users, can produce headache, jitteriness, abnormally rapid heartbeat (tachycardia), convulsions, and even delirium. Near-fatal doses cause a crisis resembling the state of a diabetic without insulin, including high levels of blood sugar and the appearance of acetone-like substances in urine. The lowest known dose fatal to an adult has been 3,200 mg – administered intravenously by accident. The fatal oral dose is in excess of 5,000 mg – the equivalent of 40 strong cups of coffee taken in a very short space of time. ” Source Not many people, even caffeine addicts are going to drink 40 cups of strong coffee.