We hear the words “toxin” and “toxic” thrown around an awful lot lately. It seems like toxins are vaguely blamed for many of the health issues in modern society – nearly every other product claims to “cleanse” or otherwise eliminate them. But what toxins are people referring to? What exactly is a “toxin” anyway? Useyourbrainforscience.com is here with the answers.

Let’s start with some basic science. Broadly speaking, a toxin is defined as any poisonous substance that is made by an organism (animal, pant, bacteria, etc). These toxins are often made as a defense mechanism – like snake venom, or nicotine,  which is an effective insecticide for the tobacco plant. However, these are not really the toxins that most people are worried about, because many of the toxins affecting human health (or thought to) are man-made. It’s probably better just to say that a toxin is any poisonous substance. Makes sense, right?  But what is poisonous in this context?

Glad you asked. I’m a professional toxicologist, and toxicology is the study of poisons, so I spend a lot of time thinking about this question, and there is a very clear scientific answer. The answer is: everything. Everything is poisonous (or toxic) at a high enough dose. This is where we get the phrase “the dose makes the poison.”  Water is probably the least toxic substance known to man, but you can die from water poisoning just as easily as you can from drinking a mercury cocktail – it just takes more water to kill you than mercury. Therefore, water is less toxic than mercury – but both are toxins under the right circumstances. Of course, this doesn’t mean you shouldn’t drink water – most of us could probably stand to drink more water and less soda or coffee.

So it really depends on where you draw the line.  How toxic is too toxic?  Here’s a handy ranking of some common substances and how they stack up against some prototypical “toxins.” The list is presented in terms of how many grams of the substance you would need to consume per kilogram of body weight. For example: you’d have to consume about 90 grams of water for every kilogram of your body weight (and do it quickly!) in order to reach potentially lethal water levels.