What is "fels-naptha"

Fels-Naptha is an American brand of bar laundry soap used for pre-treating stains on clothing and as a home remedy for exposure to poison ivy and other skin irritants. Fels-Naptha is manufactured by and is a trademark of the Dial Corporation, a subsidiary of Henkel. The soap was originally created around 1893 by Fels and Co. and was the first soap to include naphtha. The inclusion of naphtha made the soap very effective for cleaning laundry, but it was not generally safe for personal use.