How toxic is ricin is comparison to other substances? It is really bad or just just a little toxic in comparison to the really bad stuff?
Very.
The dose that killed Georgi Markov was 0.2 milligrams.
The only good thing about it is that it isn’t tremendously effective if sprayed around.
How toxic? It’s deadly.
Cheap and easy to make, a few grains can constitute a lethal dose. It must be inhaled or ingested, it does not easily cross the skin barrier.
A few cites-
Very toxic. From the overview:
Ricin is a potent protein toxin derived from the beans of the castor plant (Ricinus communis). Castor beans are ubiquitous worldwide, and the toxin is fairly easily produced. Ricin is therefore a potentially widely available toxin. When inhaled as a small particle aerosol, this toxin may produce pathologic changes within 8 hours and severe respiratory symptoms followed by acute hypoxic respiratory failure in 36-72 hours. When ingested, ricin causes severe gastrointestinal symptoms followed by vascular collapse and death. This toxin may also cause disseminated intravascular coagulation, microcirculatory failure and multiple organ failure if given intravenously in laboratory animals.
As you know, Markov was injected with Ricin via the tip of a trick umbrella.
Apparently, the use and effects of aerosolized Ricin are entirely theoretical at this time:
I remember reading that a single molecule of the poison is sufficient to kill a living cell by disturbing the metabolic pathways.
slight hijack - from the emedicine site above, I read this: “This basic structure of ricin is similar to those of the botulinum toxin, cholera toxin, diphtheria toxin, tetanus toxin, and insulin.” Ok, ricin, botulinum, cholera being similar, I can kind of get. But insulin? Is insulin considered a toxic substance?
I don’t know abou tthat, but I do know what scares the hell out of me- ricin is considered a “kitchen” substance, which means that in my kitchen right now, I probably have the right chemicals to distill out the ricin protien from the rest of the castor bean.
Holy cow.
Apparently, the white supremacist movement in the US has had ricin for decades. One group (the “we hate everybody else psychos,” one would assume) was busted in the 1980’s with 200 lethal doses in their possession. But it doesn’t appear that they’ve been caught trying to kill anybody with it.
You may have read that in ‘Medical Toxicology - Diagnosis and Treatment of Human Poisoning’, 1988. - “It is believed that a single molecule of abrin or ricin is sufficient to kill a cell.”
It is extremly simple to extract ricin from castor bean, but very dangerous. Ricin used to be used as a varmint poison in days of yore, but many of the peddlers of this stuff died whilst trying to make it.
I read that as well, but in Jurassic Park. 
Is there any know ‘antidote’ for ricin poisioning?
Well, a previous cite says that 0.2 milligrams has been a lethal dose, so this group must have had about 40 milligrams of ricin. Where did they have it hidden, under their thumbnail? This is an incredibly small amount – about the weight of a few sesame seeds. In fact, I wonder why they had so few lethal doses around – seems like refining the beans from a single plant would likely give you several hundred lethal doses.
I don’t believe that this is correct.
So you’d need something like 100 mg, not 0.2 mg.
From the above:
The stuff in the envelopes was probably dried bean mash, which is about 5% ricin. You’d need about 100 mg / 5% = 2000 mg = 2 g of that stuff injected into you to kill you, or some larger amount swallowed or inhaled.
According to http://www.emedicine.com/emerg/topic889.htm the LD50 for aerosol or parenteral (i.e. by injection) exposure is 3 µg/kg. So, 0.2 mg in an adult is a reasonable lethal dose.
Sigh… I’ve grown castor bean in my garden; it’s a striking, interesting plant. Like angels trumpet, foxglove, monkshood, morning glories, poppies…
Someday all of that stuff will be banned, probably. Always some psychopathic freak to mess things up for the rest of us.
Hampsets ate my post last night - probably killed them.
There is no known antidote once ricin has started having an effect. If swallowed, lastric lavage, induce vomiting followed by activated carbon would be a good idea. I didnt know about Vitettas work - thanks Desmo.
The lowest **subcutaneous ** lethal dose for man(LDLo) is 0.043 mg/kg. So maybe 3-4 mg for Markov.
Oral LDLo in man is 0.3 mg/kg
From RTECS - Register of Toxic Effects of Chemical Substances
Ricin can be very easily extracted and purified to a powder, much more than 5% ricin, assuming the person doesnt kill them selves in the process.
How much ricin in a single castor bean? Would eating one kill you?
How about animals? Does anything in nature eat castor beans?
If you ate a castor bean it would probably pass through without any damage. You would have to chew it up well for there to be a toxic and possibly fatal dose of ricin releasd. The beans contain 0.1-1% ricin - a fair bit - but it is well bound up.
Leaves contain less ricin than beans.
Ricin beans and leaves are extremely toxic to livestock. I am looking in Dangerous Properties of Industrial Materials and there are LDLo’s for a whole bunch of different critters - not hampters though. Another LDLo **oral ** for humans published here is 2mg/kg.
Why is ‘hampsters’ so hard for me to spell. :wally
Here you go:
Probably because everyone else spells it wrong too.
A hamster is a fuzzy little rodent.
A hampster is a lidded basket in which dirty fuzzy little rodents are placed prior to being taken to the cleaners, or maybe not.