The other white powder that can kill you

>Even more frightening is how easy it is to take too much pure caffeine. One brand recommended that consumers use a “1/32 teaspoon” to measure a safe amount. For comparison, a “pinch” of salt is generally considered to be one-sixteenth of a teaspoon.

If I were going to do something like that I'd dissolve a teaspoon in two gallons of water and use a cup.

Caffeine is one of those drugs that can sneak up on you. LD 50 is actually pretty high - it's usually quoted as 75-100 cups of coffee in an adult. The problem is the curve is wider than most drugs. Some people can handle truly massive amounts, but you're on the other side of the curve you can die from a comparatively small dose.

These sorts of warnings have been going out since at least the 1980s. See https://news.ycombinator.com/item?id=10161818 where I found a 1988 newspaper article that said:

> King said abuse of caffeine pills is fairly common among the teens and young adults treated by her [drug treatment] program. ... Sixteen people in North Carolina have died of caffeine poisoning since 1970, all from pills.