why is poison measured in metrics of “can kill X of Y”?

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the measurement doesn’t make sense to me, why is the deadliness of poison measured in how many of something it can kill? i understand the animal, such as an elephant, is important since bigger animals need larger quantities of or more deadly poisons, but what does it mean when its said poison can kill “a herd of elephants”? how do you know that one drop can kill a multitude of individuals?

In: Chemistry

6 Answers

Anonymous 0 Comments

Drug doses are calculated against the LD50 or “Lethal Dose 50%” meaning that dose has a 50% chance to kill the subject. The unit of measure is mg/kg.

So lets say something has an LD50 of 100mg/kg. That means a 5g dose has a 50% chance to kill a 50 kg person and a 10g dose to kill a 100 kg person.

“Enough poison to kill a herd of elephants” is just newspaper speak. Doctors and pharmacists and chemists don’t talk like that. You’re safe to mentally replace that garbage with “A shit-ton of poison.”

Edit: The trick is that some drugs like fentanyl have lethal doses at like… 0.025mg/kg so if someone is caught with a SINGLE GRAM of fentanyl, that’s enough fent to kill like… 500 people. Instead of reporting “man arrested with a gram of fent” you get to print “man arrested carrying enough fentanyl to kill 500 people.” It’s sensationalist garbage reporting.

Double Edit. I’m not a doctor. I’m making up fentanyl numbers using a quick google on lethal dosages.

Anonymous 0 Comments

Because if 0.5 drops can kill one elephant, we know one drop can kill two.

It’s simple mathematics.

Anonymous 0 Comments

Humans are really bad at understanding the scale of something when it’s at extremes so you give something relatable to base off of like a liquid drop, physical grain, gram, etc.

Anonymous 0 Comments

It’s a dramatic way to highlight the potency of the poison. Like saying a car has horse-level horsepower, but scarier.

Anonymous 0 Comments

This isn’t the way it’s expressed in any official context, it’s just an easy way to understand the magnitude. For example, you can say the average bite from a particular adult snake contains 10 mg of a toxin with an LD50 of 0.1mg for an adult human. But that’s wordy and hard to conceptualize. On the other hand if you say the bite of that snake could kill 2 elephant, it’s easy to understand that it’s extremely toxic.

Anonymous 0 Comments

I think it is just a matter of people being absolutely terrible at understanding very large and very small numbers. Numbers in those categories have to be put into something that people can visualize, so you get things like how many elephants can a spoonful of poison kill or how many empire state buildings full of $100 bills is the US national debt. The understanding of those numbers tends to be massively incorrect otherwise.