to cover grey?

L'oreal Preferance. Not the grocery store version, but the beauty supply version with the blue label that is the dye only, you have to buy the white stuff (what IS that called?) separate. It's the only one I've found that truly covers gray without ruining the hair or getting brassy right away. I sure wish I could find a more natural alternative, but so far none of the Black-Walnut versions do the job. :(