Deadliest Toxin?

Depree, Jonathan A depreej at
Wed Jan 8 09:35:43 EST 1997

In article <5au01u$ohb at> tivol at (William Tivol) writes:
>From: tivol at (William Tivol)
>Subject: Re: Deadliest Toxin?
>Date: 7 Jan 1997 17:10:22 GMT

>Depree, Jonathan A (depreej at wrote:
>: In article <Pine.SOL.3.93.970103173910.5407A-100000 at> jbullard at NUN.OIT.UNC.EDU (Jim Bullard) writes:
>: >On Fri, 3 Jan 1997, Anubis Ragnarok wrote:

>: >> Hello,
>: >> 
>: >> I was wondering what the deadliest toxin known to man was? I am new to biology.
>: >> 
>: >> -Anubis
>: >> 
>: >ricin> 

>: Close, but no cigar. Last I heard the deadliest toxin known was a neurotoxin 
>: produced by Clostridium botulinum.

>        Is this restricted to *human* toxins?  If not, one of the colicins
>might qualify.  I think it takes only one molecule to kill the target or-
>ganism.  Of course, that is only an E. coli, but if it truly takes only
>one molecule, it will be hard to beat that record.  On the other hand, in
>terms of mg per kg, perhaps colicins are not so deadly.

One molecule of ricin will kill one cell. I suspect that one molecule of 
botulinus toxin will kill one nerve cell. The bacterial toxins are pretty 
deadly, I seem to recall that three reasonably active cells of C tetani will 
produce enough toxin to kill an average human in good health.

Actually human toxicity is a bit problematic. Feeding toxin to students until 
half of them die is frowned upon in most societies. What we usually do is find 
the dose for rats (or similar animals). There is some evidence that some 
toxins (like tetrodotoxin from puffer fish) are much more toxic whereas others 
(like dioxin) are much less toxic to humans. It'll do until we find something 

It seems I left that paper behind when I left home so I can't give specifics.
Jonathan Depree,
Lincoln University, P.O. Box 84, Canterbury, New Zealand.

Socrates was a famous Greek Teacher who went around giving
people advice. They killed him.   (school history howler)

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