Re: BIO/LAW: FDA and Olestra

From: Dave Sill (
Date: Sun Feb 18 2001 - 20:56:23 MST

James Rogers <> wrote:
> On Sat, 17 Feb 2001, David Sill wrote:
> >
> > Castor oil doesn't cause diarrhea because it's undigestible. It causes
> > diarrhea because it contains a trace amount of ricin, a substance which in
> > larger--but still quite small--amounts causes death by dehydration due to
> > uncontrollable diarrhea.
> Ricin is a cytotoxin (ribosome inactivator actually) and has nothing to do
> with Castor oil, other than originating from the same plant.

Maybe I was misinformed, although I don't see how castor oil can avoid
having minute trace amounts of ricin since the oil comes from the bean,
which contains ricin. Yes, I know ricin is water soluble--that would
certainly prevent high concentrations of ricin in the oil, but insolubility
is really just very low solubility.

But my original point--that castor oil doesn't work as a purgative because
it's undigestible--is correct. The mechanism doesn't seem to be well
understood. The two explanations I've found on the net seem as likely as the
trace ricin hypothesis I'd heard. One is that some component of the oil
stimulates the bowel muscles. The other is that ricinoleic acid prevents
absorption of liquids by the small intestine.

> Diarrhea is
> not how it kills you, though that sometimes occurs as a symptom of people
> with late stage ricin poisoning.

You're right.

> If Castor oil contained ricin even in
> small quantities, you would *not* want to consume it. A lethal dose is
> less than 1 milligram, and the damage is irreversible and generally
> unstoppable once in the system.

There are many highly toxic substances with medicinal applications.


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