As a geek of science fiction, there are certain things that drive me nuts in a sword and sorcery tale. The new Conan movie. I loved the ship, it was more Oriental style; but nothing on the ship was secure, one breeze and everything goes. And he kept putting the sword in the ground, that ruins the edge.
Poisons. Natural poisons are readily come by; the problem is, getting it in the person. Now this is old types, not some of the modern ones. Cyanide is available natually, you can find it in pit fruits. Arsenic was popular too. Some from mushrooms. Getting somebody to eat enough of it without noticing the flavor is the problem. Supposedly, Claudius died of poison. Quite of few rulers had been poisoned.
https://www.youtube.com/watch?v=vQqJh5AzSho from Game of Thrones. (not safe for work)
Yea, right, one drop. How did you make this and how do you control it? How do you put it on your weapons and not worry about getting it on yourself? Wait she had the antidote. There really are not that many, mostly just stay alive until the body deals with it.
Then there was Killjoys on SciFi channel. Woman gets nicked with a poison dart. But it slices her arm and goes on to somebody else. Where upon she tastes it, identifies the poison (okay seems she was raised to be an assassin) then ties a scarf over the wound. What? tie above the wound and let the blood wash it clean. The way to use poison on weapons is to get into the system, hence the phrase "cloak and dagger."