As a side note: Some tests were done with "poisoned arrows". Arrow heads were made with grooves to retain a liquid poison via capillary action, then fired.
The speed of passage through the air pretty much scattered the venom in flight. Unless you were firing point blank, it meant nothing.
Arrow heads could be specially prepared well in advance, but they had to have grooves and hollows for poison, and then they'd have to be covered in wax, to protect it. Nobody ever did the "Dip and shoot" thing we see people do in games.
The tribes in Africa and South America (and Southeast Asia for all I know) that traditionally poisoned their arrows were more stone age, and didn't use arrow heads at all. Their arrows had sharpened wooden tips that they'd bake dry near a fire, to harden them. Once dried they'd soak the wood in the poison, and it would be absorbed.