or your players
Poison is generic. Venom is specific to normal method of delivery (e.g. snakes and bees).
Swallowing venom may or may not hurt you. Probably not a great idea, but there’s a better chance you’ll be okay.
Getting a known poison stabbed/injected intravenously seems likely to be pretty effective, but it depends on the mode of action. Blood goes everywhere in the body, so it will likely find its target eventually.
Most of them would be denatured by stomach acidity but the risk of something like paradoxin finding a small route into your blood stream is too damn high.
When it comes to venom that is also used as a toxin in other species, though, and is a big killer of humans, the crown goes to https://en.m.wikipedia.org/wiki/Tetrodotoxin which is used as both a poison against predators for things like pufferfish and a venom for things like the blue ringed octopus.
