I have a short story called “caffeine and ultraviolet”. Some people think caffeine is harmful – which is not the inspiration for the story, but it was interesting to come across this page recently. Apparently, you’d die of caffeine poisoning if you drank 118 cups of coffee – except you wouldn’t make it to 118 – you’d die of water poisoning first. So the water in a cup of coffee is more “poisonous” than the caffeine in it. It’s an abuse of language to call it poisonous, of course: too much of anything can kill you.