Fuller's earth is a kind of absorbent clay that got its name back in the days when English textile workers combined it with water, urine, and the cleansing herb soapwort (Saponaria officinalis) to extract grease and oil from newly woven woolen cloth. "Fuller" is an old name for a worker of cloth, hence the name "fuller"s earth" for this clay. Its technical names are attapulgite or montmorillonite.
Today, fuller's earth is most commonly used in the United States in kitty litter, but it is also widely used in industry to absorb oil and grease, as a carrier of pesticides, as a flow control agent in animal feed as well as in adhesives, asphalt emulsions and tiles, paint, paper coating and textiles. You can use it at home to absorb oil spills in the garage or driveway or to remove wine stains from non-washable materials. Fuller's earth is also contained in some facial masks and is considered so safe that you can use it instead of baby powder when diapering an infant.
You'll also see attapulgite listed among the ingredients in some over-the-counter antidiarrheal treatments. Here, its absorbent qualities are believed to trap the bacteria causing the problem and help remove them from the body.
All told, fuller's earth is a very safe and useful product. However, the dust it can throw up may irritate the eyes. While breathing in the dust can't be entirely healthy, you probably would have to inhale large amounts over a long period of time to develop any medical problems. Prolonged heavy exposure can lead to scarring of the lungs (pneumonoconiosis), but this isn't common even among fuller's earth workers, and the one case I came across in a search of medical literature turned out to be relatively mild . I doubt that you're going to suffer any serious, long-term health consequences from your exposure to fuller's earth. But if you are at risk for further exposure, be sure to wear a protective mask.
Andrew Weil, M.D.