I've never used castor oil on my eyebrows, but I'ved used it to regrow part of my hair line that I burnt off (long story). Worked like a charm! Most people use Jamaican Black Castor oil, which you can get at health food stores or online. I used the stuff I got at the drugstore (it's in the laxative asile) and it still worked (it might work faster with the JBC-I don't really know what the specifics behind the process are).