Poison isn't as popular among murderers as it once was, and these days killers prefer guns and other deadly weapons to poison because they're easier to acquire and deliver an instant result.
But if you've pissed off someone with a flair for the dramatic and a healthy passion for antiquated murder mysteries then you may want to watch this SciShow video and learn how to detect the "undetectable" poison they've been feeding you.
It's required viewing if you have a butler in your employ...
-Via Geeks Are Sexy