During Prohibition, the US Government put toxic chemicals into any products that contained alcohol, just to make sure nobody would drink them. Now, Prohibition is long over... but the policy of adding poison to alcoholic products has never ended. Here are the deadly additives that are only there to keep you drinking stuff.

The Aversive Agents

These are the gentlest ingredients that are added to things like hand sanitizer, to discourage you from drinking them — and they’re basically pepper spray in liquid form. They’re called “pungent agents,” and they consist of piperine, the molecule that’s responsible for the kick in black pepper and capsaicin, the molecule responsible for the kick in chili peppers.


And even these toxins have a deadlier version. Resinferatoxin is a chemical found in a Moroccan cactus. It stimulates the same receptors as capsaicin. The good news is, it stimulates them more powerfully than capsaicin. The bad news is less than forty grams of it is potentially fatal for humans. Even a small amounts can leave people reeling and in pain for hours.

Less gentle are the bitterants. The most bitter of these is denatonium, which is most often used in anti-freeze. Anti-freeze is, on its own, extremely sweet. This made it dangerous to have in a house with small children. Denatonium, the bitterest substance known to humans, is added to antifreeze to drown out the sweet taste. Denatonium doesn’t actually do any harm. Neither do many other bitterants, like quassin, which is used as a folk medicine, and sucrose octaacetate, which is used in pesticides but does not do harm to humans.


Less harmless is the bitterant brucine. Brucine is probably one of the chemicals that led to humans developing an aversion to bitterness. It comes from the bark of the same tree that gave people strychnine, it’s chemically similar to strychnine, and it is also poisonous. In fact, the only reason people don’t succumb to brucine poisoning that often is it is almost always accompanied by strychnine and the strychnine kills people first.

The Killers

We know that, during Prohibition, the government tried to stop people from drinking by making alcohol poisonous. The most reliable of those poisons were in the methyl family. Methyls share their name with methane, which has one carbon bonded to four hydrogens. Methyl groups have their one carbon atoms hold to only three hydrogen atoms, leaving them an “arm” free to hold on to a versatile variety of molecules, none of which are good for the people drinking them.

In our quest to make alcohol unappealing, we never entirely abandoned the methyl group. Unlike the aversive agents, they don’t all taste bad. Methyl ethyl ketone has been shown to cause birth defects in mice (admittedly, only at high levels of exposure), but smells like butterscotch. Methyl isobutyl ketone has no particular smell or taste. Both of these are sometimes used to denature alcohol.

But the most popular methyl poison is methyl violet. Methyl violet gives methylated spirits a beautiful, serene violet color, but it puts across the same message as a poison dart frog — consuming me will kill you. It was used even before Prohibition, when agents used the dye to stain already-spoiled cornmeal and make it unappealing (and ideally not salable) to the public. It’s been used in industrial dyeing, which has led to both devastated ecosystems downstream from dye processing plants and a focus on how to destroy the dye before it can be ingested by animals.


It’s not a good way to go. One animal study showed that methyl violet caused deep lesions in lung tissue that were eventually fatal. It also stained bile, and turned the entire lower intestinal system purple. Just as a bonus, it’s a mutagen and what’s known as a “spindle poison,” a poison that keeps cells from dividing.

Now, to be fair, the point of methyl violet is to be highly visible and to keep people from drinking.

In the absence of prohibition, most people would be perfectly content to get cheap vodka rather than methylated spirits — which are not meant to be food-grade alcohol. Still, it’s odd to think that manufacturers and governments add straight poison to their alcohols rather than countenance anyone drinking them. Isn’t drunk better than dead?

Top Image: Orange County Archives, Bottle: Wellcome Images