Scientists Say: Toxin

This refers to any substance that can kill or harm an organism — and came from a living organism

poison frog

Don’t touch! This lovely frog’s colors are a sign that it secretes a toxin. 

Abi Skipp/Flickr (CC-BY-2.0)

Toxin (adjective, “TOX-in”)

This is something that can harm or kill cells or organisms. It’s a term for a class of things that are poisonous, or toxic. When scientists measure how dangerous a chemical is, they measure its toxicity. The scientists who study these substances are called toxicologists.

But while any substance can be toxic, a toxin is more specific. Toxins are poisonous substances produced by living things. They can be poisons from frog skin or poison ivy, or venom from a snake. But many synthetic chemicals can poison, none of them is a toxin.

In a sentence

While toxic algae can poison some species of plankton, it can make others swim faster.

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Power Words

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toxic    Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.

toxicant     An agent, usually some chemical, that can produce poisoning or harmful reactions in a living organism.

toxicology    The branch of science that probes poisons and how they disrupt the health of people and other organisms. Scientists who work in this field are called toxicologists.

toxin    A poison produced by living organisms, such as germs, bees, spiders, poison ivy and snakes.

Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

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