Poisonous or venomous: Understanding the difference

Do you know the difference between poison and venom? Everyone knows that these two things are very harmful to the human body, but some people think that these two words are interchangeable. You might ask, what are the differences? Let’s talk about venom first.


Venom is a complex variety of toxins produced by a living organism to either, defend itself, help with digestion, or catching prey. Normally when one hears the word venom, it conjures the image of a snake, but many other animals have venom, such as spiders, fish, even some mammals like the platypus produce venom.

Venom is not harmful if ingested, unless one has lacerations or ulcers, as it must be injected into the bloodstream or muscles without passing the digestive tract to be effective. This does not mean that animals that are venomous aren’t also poisonous.

Several species of snakes are both venomous and poisonous due to their diet. The effects of venom generally consist of proteins which help to prevent the blood from clotting, lower blood pressure, paralyze, and eventually leading to death.


Poison on the other hand, is any harmful substance that if ingested, inhaled, or applied to the skin in sufficient quantities, will cause damage to the body. Any substance can be poisonous if enough of it is ingested in large enough quantities; water for example isn’t generally considered to be harmful, but in large amounts can lead to very dangerous results.

On the opposite side of the spectrum, a well-known poison, nicotine, which is found in many plants of the nightshade family, most notably tobacco, can cause severe symptoms with less than half a gram of material. Even some food is poisonous before you cook it! Kidney beans are a good example; if not properly cooked kidney beans cause severe symptoms with as little as four beans, under-cooking the beans causes the toxicity to increase up to five times!

Poison has been used throughout history to assassinate political figures, as a military weapon, for pest control, or personal vendettas.  

For example, a poison dart frog is poisonous, because its toxins act by touching, or ingesting the toxins found on the skin, but is not venomous because it does not inject its toxins for them to be effective. While a platypus is venomous but not poisonous since it uses a spur on its hind leg to envenom.

In short, if it bites or stings to infect, its venomous. If it is ingested, touched, inhaled, or absorbed, its poisonous.