Venoms vs. Poisons

Generally, a poison is a toxic substance that is distributed throughout the tissues of an animal's body via inhaling, absorption or intake. For example if the poisoned animal in question is eaten by another creature the toxin will cause a reaction thus poisoning the system of the second creature.
Venom is made up of natural enzymes to form modified saliva introduced into a closed system by being forced in through breaking the skin. Anyone can drink pure venom without any side affects if no open wound in the mouth or throat exist

Venom is only a poison if it enters a closed system through the skin. If not it is harmless.