This article is part of the Science in Sci-fi, Fact in Fantasy blog series. Each week, we tackle one of the scientific or technological concepts pervasive in sci-fi (space travel, genetic engineering, artificial intelligence, etc.) with input from an expert.
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About the Expert
Since getting her Ph.D. in Toxicology in 2015, Megan Cartwright Chaudhuri has worked as a freelance medical writer and editor. Her science non-fiction has appeared in Slate and Visionlearning, while her science fiction has appeared in Analog, Crossed Genres, and the forthcoming Futuristica Volume 1. Megan lives near Seattle with one husband and two cats.
Poisons in SF/F
One of the most dramatic scenes in George R.R. Martin’s A Storm of Swords [SPOILER WARNING: Skip this paragraph if you haven’t read/seen it] is the agonizing death of psychopathic King Joffrey. While being an ass at his wedding feast, Joffrey begins to choke on some wine. Gagging, he claws at his swelling throat, his face darkening as he fights for breath amidst the screams of his guests. When Joffrey collapses and dies, the reader in me wants to cheer. But the toxicologist in me wants to groan: Another instantaneous death from poison sprinkled in food.
There is so much more that a writer can do with poisons. The next time you reach for something to torment your characters (psychopaths or not), I hope you build a better, more interesting poisoning that avoids these common tropes and misconceptions.
Trope #1: All poisons do is KILL.
Whether it’s arsenic or table salt or water, every chemical can kill you, if you take enough of it in a short span of time. Some chemicals, like cyanide or the “strangler” in A Storm of Swords, are so potent they will overwhelm anyone at miniscule doses. However, most chemicals have a gradient of effects that get worse as more chemical gets into your body. The amount of chemical that causes those effects varies from person to person, with people being extra vulnerable when they are very young or (for example) have failing kidneys that can’t filter chemicals out of their blood.
A writer can do a lot with this gradient of effects, which toxicologists call a “dose-response.” Why kill a character right away, when you can force them to empty their bowels in public, riddle his scrotum with tumors, or make her give birth to one-eyed children? Here are a few examples of real poisons and their gradients:
- Neurotoxicity. Many animal and insect venoms, as well as pesticides, poison the nervous system by interfering with neurotransmitters—the chemical signals relayed between nerve cells. While sometimes lethal, these poisons can also cause embarrassing and painful effects like drooling, uncontrolled diarrhea, convulsions, and paralysis.
- Cancer. At high doses, many poisons kill quickly. But at low doses, taken over time (such as in drinking water, or encountered at work), many can still cause terrible diseases. Arsenic is a perfect example. Small amounts of this element contaminate drinking water in Bangladesh, where it causes skin cancer and heart disease. Another example is a benzo[a]pyrene, a component of soot, which caused scrotal cancers in chimney sweeps during the industrial revolution.
- Reproductive toxicity. Many chemicals have little effect on healthy adults, but do awful things to a developing fetus. One infamous example is cyclopamine, a toxin in a pretty flower called corn lily. Cyclopamine causes babies to be born with one eye and a missing nose/mouth. Another example is methylmercury, which slips across the placenta and concentrates inside the fetus’s brain to devastating levels.
Trope #2: Poisons work when you eat and drink them.
A poison works when it can interact with a vulnerable part of the body. While a GRRM character’s throat is clearly the part vulnerable to the strangler, for many other poisons the vulnerable organ (like the brain) is tucked away. That means that these poisons have to get into the bloodstream to reach the vulnerable organ.
Eating and drinking—ingestion—are surprisingly inefficient ways to get poison into the blood. If the stomach’s full of food, the poison travels more slowly out of the stomach and into the bloodstream, giving the body more time to potentially clear it. A lot of poisons (especially metals like the elemental mercury in thermometers and toys) also don’t cross easily from the stomach to blood, meaning they mostly pass out of the body as toxic poop.
Ingestion aside, here are other ways you can get poisons into your characters:
- Injection. Whether it’s fangs, poisoned arrows, or a needle, a poison injected directly into the bloodstream usually finds its vulnerable organ the quickest.
- Inhalation. The lungs are a marvelous way to quickly get a poisonous gas or vapor into the blood (just think about how anesthesia is usually administered!). But the lungs offer another, unique way to get poisoned. Very small particles—from asbestos fibers to nanomaterials like quantum dots and single carbon nanotubes—can get lodged in the lung and keep damaging the delicate tissue.
- Absorption (skin, eyes, vagina, anus). Some poisons just sit on your skin and do nothing. Others, like certain pesticides and chemicals that dissolve in fatty oils, can slowly slide inside and enter the bloodstream. Skin absorption is usually a slow way to get a poison into the blood, although it gets a little speedier if the skin is delicate, warm, or damaged. By comparison, a splash of poison to the eyes can hurt both the eyes and get more quickly into the blood. And a poison applied to the thin tissues inside the vagina or anus is going to get into the blood even faster (but I’ll leave it to the writer to figure out how to deliver that poison!).
How to do it right!
Whether you’re devising your own poison like the strangler, or picking one from real life, here are some questions to think about to make your poisoning as unique and believable as possible:
- How much poison is needed—a single speck like cyanide, or a heaping handful like lead?
- What is a poison’s gradient of effects at different doses?
- Who is the most sensitive to its effects?
- What is the vulnerable part or system of the body?
- How does it come into contact with the vulnerable part?
- If the poisoned character survives, what are the long-term effects on their body?
- A is for Arsenic: The Poisons of Agatha Christie, by Kathryn Harkup
- Agency for Toxic Substances and Disease Registry – Toxic Substances Portal
- American Association of Poison Control Centers
- American College of Medical Toxicology Frequently Asked Questions from the Public (Disclosure: I’ve received money from ACMT to write continuing medical education materials on toxicology).
- Casarett & Doull’s Toxicology: The Basic Science of Poisons (the bible of toxicology)
- Me! I love answering questions about toxicology. Feel free to contact me at meganchaudhuri AT gmail DOT com, and I’ll give it a shot (or forward you to another expert if I can).
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