Poisons appear in some of the most popular works of fiction. A toxicologist explains them

People have used poisons throughout history for a variety of purposes: to hunt animals for food, to treat diseases and to achieve nefarious ends like murder and assassination.

But what is a poison? Do all poisons act in the same way? Does the amount of the poison matter in terms of its toxicity?

I am a toxicologist who studies how chemicals affect human health, particularly when they cause harmful effects. As a fan of mystery and detective stories, which often feature the use of poisons, I’ve noticed a few poisons that turn up repeatedly in books, television and movies. How they really work is as fascinating as how they’re deployed toward evil ends in fiction.

What is a poison?

The 16th-century physician–alchemist Paracelsus, considered to be the father of toxicology, once wrote: “What is there that is not poison? All things are poison and nothing is without poison. Solely the dose determines that a thing is not a poison.” By this adage, any substance can be a poison with the appropriate amount.

Many people intentionally expose themselves to chemicals like ethanol through alcoholic beverages, nicotine through tobacco products and botulinum toxin through botox treatments at relatively low doses and suffer minimal adverse effects. However, at sufficiently high doses, these chemicals can be lethal. The body’s...

Read more