Sunday, November 28, 2010

The Castor Canundrum: Miracle Bean or Toxic Curse?

Castor Oil:
Castor oil is a wonderfully unique oil, rich in glycerin esters of ricinoleic acid. It is widely used throughout the world in everything from industrial applications to folk remedies and, of course, in soap! It's unique composition adds many wonderful qualities to soap. It promotes a rich bubbly lather, is very soothing and acts as a humectant to draw moisture to the skin. But it is not without controversy.

Background: How did Castor Oil Get Such a Bad Rap?
  • Castor beans contain ricin.
  • Ricin is one of the most toxic substances found in nature. According to numbers released by the Center for Disease Control (CDC), one castor bean contains  enough ricin to kill 300 people (
  • Ricin has been a known biological weapon since WWI and is considered a category B threat by the CDC, meaning it is in the second highest category of agents
  • There is no known andecdote for ricin poisening
  • Castor plants are also highly allergenic
  • The majority of castor oil is produced in India, Brazil and China
Castor Oil itself does not contain ricin. It is removed during the extraction process, but it is in the waste "mash" that is produced. So although castor oil iself is not a toxin, people seem to have two main concerns:
  1. human rights concerns surrounding the factory and farm workers who harvest and process the beans
  2. the disposal of the ricin rich "mash"  
Castor and Human Rights: The Claim
Over and over again, people purporting to take a moral stand  use the same argument to demonize Castor beans. Word for word, that argument is this:

"Allergenic compounds found on the plant surface can cause permanent nerve damage , making the harvest of Castor beans a human health risk."

You can find this exact phrase here and here and here and here and, sadly, even here on one of my FAVORITE company's blog.

It is also written word for word on several forums, including:

And the list goes on and ON AND ON. 

I'd be willing to bet most of these people pulled this off of Wikipedia, which cites their source for their information as:  Go to this site and you'll see there is no further citation, no stats and no data to back it up. In fact, I can not find ANY hard stats or data on ANY of the sites that use this phrase.  

The Facts:

  • I found no substantiated evidence that exposure to the plant's leaves causes permanent nerve damage, in fact Castor plants grow quite readily throughout the United States (predominantly in Florida, Texas and California). They are even used as ornamental plants in gardens.
  • However, prolonged contact with the plant's sap, flowers, seeds or leaves may result in a rash. If introduced to the eye, conjunctivitis may develop (you can read more here). 
  • Also, like ragweed, the Castor plant (Ricinus communis) does produce a great deal of pollen, which can cause allergies. In severe cases, people may develop asthma.
  • Perhaps the most documented effects of Castor are seen in the factory workers where the oil is produced. Factory workers exposed to dust from the Castor seeds may develop allergies and suffer from asthma (you can read more here). 
So how bad is all this?

Well, the same risks and ailments are common among
So, in my view, the negative effects associated with Castor processing are really more of an occupational hazard than a call to arms or reason to boycott. This site published a fairly comprehensive table outlining a variety of biological agents that have been linked to occupational asthma across a variety of occupations.

I think some people like to target Castor because it is largely produced in developing countries. They argue that the workers are at greater risk because of laxed labor laws etc. But I think the above studies, which were conducted all over, from Papua New Guinea to Croatia to Tennessee demonstrate that the same occupational hazards exist everywhere.

The fact is, many of the foods we eat and the things we enjoy entail some level of occupational hazard for the workers involved. From firemen and cops to coal miners and crab fishermen, people risk their life every day so that the rest of us can enjoy the many things this world has to offer. It is simply ridiculous to target Castor oil and boycott it as if it were a singular offender.

Disposal of the Ricin Rich Mash
Another concern people frequently have regarding Castor oil is the waste mash that results from processing the beans. The mash contains all of the deadly ricin and is highly toxic, so can it really be disposed of safely? Yes! The "waste" actually has many wonderful uses:
So relax... don't worry. That Castor oil you buy isn't likely to be contributing to the development of biological weapons by terrorists... nor is it likely to be destroying the nervous systems of exploited workers in third world countries. Castor may be deadly, but it is a wonderful plant with hundreds of beneficial uses throughout the world. 


  1. I love the depth of research and time you put into your articles, they are very informative.

    Another antidote I read of Castor oil's wild and assorted past is that it was used as a form of torture in futile Italy, it was fed to prisoners because it is a very strong laxative, they often perished probably due to dehydration. Yikes!

    Thanks, your blog is great!

  2. Thanks City Mouse! I'm so glad you enjoy it :) And thanks for sharing that bit about Castor oil's past... What a wild little bean!

  3. Thank you for taking the time to write such an informative post!