This is a true claim, after researching this article, I found that it quotes Dr Robert Glatter. Dr Glatter has a history of working with drugs, including caffeine, and is a very reliable source. since he is quoted in more than one article and both have the same claim, I find both to be true. This article is about Dr. Galtter's findings and is verified by him. While caffeine is a harmful drug, it takes a lot to kill you; you would need a lot of coffee or a teaspoon of pure powder caffeine, which is around 28 cups of coffee, instantly.