Venomous or poisonous?

Is there any defined difference between creatures that are described as venomous and those described as poisonous or are the two terms interchangable?

Something in the back of mind says the difference may be down to how the substance is administered e.g. biting or stinging but i’m far from sure.

A venomous animal is one that actively delivers venom, such as through a bite or sting. A poisonous animal simply stores poison in parts of its body as a defense, such as some species of tree frogs.

I believe that venom is a subset of biological poison that is administered sub-cutaneously, while poison is usually absorbed through the epithelial linings, like your skin or stomach. Therefore, snakes, bees, etc are venomous and toads, plants, etc are poisonous.


Usually, a poison is a toxic substance that is distributed throughout an animal’s body. These animals don’t have any mechanism to deliver the poison. You eat it, you suffer from it.
Venoms are produced, stored and delivered by a very specific set of organs, and venoms are not distributed in the animal body.

Venomous = they inject a substance into you that makes you ill or dead. Injection can be through teeth, stings or sprays.

Poisonous = something you actively ingest that makes you ill or dead - holding, eating, licking, inhaling, etc.

It’s just a matter of who’s doing the action.

Venom is a more specific term; it refers to toxic substances secreted by animals. Poison is a more general word used to describe any substance which can harm or kill. Snake venom and arsenic are both poisons, only one is a venom. That’s my understanding of it. Here’s what Merriam-Webster has to say:

What about toads, then? They fit both categories. The poison of a toad is the secretion of a specialized organ (the parotoid glands), yet there is no delivery mechanism–the toad fits the “you eat it [or attempt to], you suffer from it” criterion.

Toads are poisonous, because they do not actively deliver the poison to the victim. You have to touch the toad to be affected; the toad cannot spray you with poison.

Venom is a type of poison, so a venomous animal is technically poisonous as well. The term venom means that the poison is actively delivered, not passively. A bite would be an active delivery method and toxic skin secretions is passive, hence not venomous.


I agree. I think the presence or absence of a delivery mechanism is more significant than whether the toxin is a localized secretion or is distributed throughout the animal’s tissues (as in the case of caterpillars that are poisonous because they eat toxic plants).

When I worked in a venom lab, the stuff we extracted from toads and poison dart frogs was referred to in our catalog as venom, possibly incorrectly. The descriptions of the components of the amphibian poisons in our catalog always referred to them as toxins, such as batrachotoxins and pumiliotoxins (these are from dart frogs). We never used the word poison when referring to the stuff. The dictionary entry I mentioned above does suggest that delivery via biting or stinging is part of the concept of a venom, but back in the 70s when I was in that business, we did not make that distinction.

That’s interesting–to me it makes more sense that one would get poison from a poison dart frog. Were there any animal secretions that were referred to as “poison” in your company’s catalog? I’m curious because I have encountered people that would call any toxic animal secretion venom, regardless of the delivery method.


Can’t remember where I heard it from, but:

If it bites you and you die, it was venomous. If you bite it and you die, it was poisonous.

Nonsense! I remember quite clearly that the toad in Dave Barry’s book Big Trouble squirted venom into the face of one of the main characters. And if you can’t trust Dave Barry to accurately describe the venom-delivery mechanism of a hallucinogenic toad, who CAN you trust?!

The catalog always used the word venom for the products we extracted, which was mostly snake venom. We had a few contracts for spider, scorpion, frog and toad venom. The dart frogs were referred to as dendrobatid frogs in the catalog. At that time, the most frequently used common name for them was poison arrow frogs, later replaced by the more correct poison dart frogs.

To collect poison or venom from a frog or toad, we placed the animal on a piece of glass and subjected it to a mild electric shock, which prompted them to secrete their venom onto the glass.