I am allergic to traditional hair dye does anyone have suggestions besides Henna for graying hair?

I've heard about Organic Color Systems, only problem is that the color requires a peroxide developer for it to work. A friend of mine had recommended this new product from Cosamo called Love Your Color. its a semi permanent color (means it washes out) and has 0 ammonia, 0 peroxide and 0 PPD. Great for all those allergic and easy to use from home.