What's Lethal in Miniscule Amounts?

How many known chemical compounds are there that would kill a healthy, typical-sized adult if they ingested one milligram of the substance? Probably too many to list here, right?

What about one microgram?

How about one nanogram?

Anything out there that could kill you in picogram range?

What if we included radioactive elements?

On second thought, let’s speak in terms of the LD-50 model of toxicity, so y’all won’t jump down my throat pointing out that my question is poorly phrased from a statistical standpoint.

30–60 mg (0.5-1.0 mg/kg) of nicotine can be a lethal dosage for adult humans. 10 mg for a child. And it only has to be spilled on the skin. Cite.

And is anyone else relieved that the title of this thread does not include the words “NEED ANSWER FAST”?

VX has an LD50 of 10 milligrams and is, I’m told, one of the most lethal substances ever synthesized, so at 1 milligram and under, you’re talking some seriously lethal sh!t.

Edit: Sorry, I read over the “ingested” part of the OP. The cited LD50 for VX is for skin contact.

The LD50 of botulinum toxin is estimated to be 1ng/kgbody mass.

Anthrax would have to right near the top of the list.
80 nanograms is thought to be lethal to almost everyone exposed to it: http://www.hinduonnet.com/fline/fl1822/18221310.htm

Botulinum toxin LD[sub]50/sub 0.00001mg/kg

Ricin LD[sub]50[/sub] 0.3mg/kg

How much mass would a lethal total body irradiation dose (>7.5Gy?) have?

That has to be the most “miniscule amount” of “stuff” that’s lethal, right?

IIRC, there is a substance when you “overcook” Meth. It is lethal in 1 ppm. True or not, I don’t know. I believe it was in a local newspaper about the dangers of Meth labs next door.

Sure, but anthrax is a bacterium, not a chemical compound. It replicates.

Speaking of which…would prions count?

Well, if you relax that LD-50 restriction, there’s always that one energetic cosmic ray that happens to generate that one free radical that mutates that one strand of DNA. But it’s not even close to * reliably * lethal, and it would probably take a considerable amount of time for the genetic Rube Goldberg machine to reach its conclusion.

Indeed. Reports I’ve seen suggest that other outcomes are far more likely.

Prions are polypeptide sequences with no replicative capabilities, right? If they are, then they would count.

They are believed to be misfolded proteins. Whether they can “replicate” is somewhat murky. The theory is that they cause normally-folded versions of the same protein to assume the abnormal structure. Kind of like tiny zombies.

Regardless of whether they qualify, I have no reason to believe they would be lethal in tiny doses, and I can’t seem to find any cites one way or another.

I came in to mention Botulinum and ricin, but since those are already taken, I’ll just point out that “Tiny Zombies” would be an amazingly good rock band name. Also, if you wanted to inflict pain rather than kill, it would be difficult to beat Irukandji venom.

My mother found a small bottle on the ground containing this when she was walking the dog once. We didn’t know what it was and I checked it online. Then we became quite worried since it seemed to be quite dangerous. We contacted some authority about it, but they said we could just throw it away. I guess it had contained the bacteria who create the toxin, or something of that kind. The label said clostridium botulinum or something of that kind.

Huh. According to wiki, their existence is still hypothetical at this time. I didn’t know that.


Botox is Botulinum toxin, so you might find bottles of it in illegally dumped medical waste.

C. botulinum is a very common soil bacteria, and it can be found in honey too.

Polonium-210 (the stuff used to kill Alexander Litvinenko) has a lethal dose of 50 ng (ingested) and 10 ng(inhaled).

That’s total dose, not per kg (at least according to wiki)