Castor Bean/Seed Pods
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A reader and frequent poster to the Candle and Soap Making Forum wrote about a company that had said that castor oil was poisonous...and that "... they only use sulfated castor, because regular castor has some kind of toxin in it. I did a ton of research about different oils before I started making soap, and I still read articles when I see them about the properties of oils, and I have NEVER seen anything bad written about regular castor oil, in fact I use it all the time, as I assume pretty much everybody does! I know that castor beans are a poison if ingested, (saw that on Trauma, Life in the ER or something like that!) but never anything bad about just the oil."
That's a great question! From Mussolini's use of it as a torture technique, to it being a medicinal threat in Little Rascals episodes and Tom and Jerry cartoons (at about 3:08 in the cartoon), castor oil has a bit of a cloud hanging over it. But it's actually a really healthful and useful oil. It is used in foods, medicines, industrial applications, bio diesel, and for us...soap making! Castor oil is the only oil that has the fatty acid ricinoleic acid in it - and hence, it's the only oil that does what castor does in soap - and that's create a low, rich, bubbly lather. The lather is different then the light, high, bubbly lather that coconut oil makes - castor makes a richer, more creamy lather.
But is it poisonous? No...well...unless you're pressing it yourself from your own plants, it shouldn't be. The oil that soap makers get is generally "Castor Oil USP" - which stands for United States Pharmacopeia - which in a few words means that adheres to the standards of the United States Pharmacopeia and is o.k. to use medicinally/internally.
Now...that doesn't mean you can go plant a castor bean plant and start eating the seeds. The seeds of a castor plant do actually contain a very toxic poison called ricin. If you were to chew a castor bean/seed you could ingest the poison and get very sick or die. But apparently the toxin is water soluble, not oil soluble, so it is not expressed into the oil when the oil is pressed. So whether you're using sulfonated castor oil (castor oil that's treated with sulfuric acid to make it water soluble), or just regular castor oil, you're soap should be just fine.
Here's some more interesting information on castor oil and castor bean plants:
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