the smell is horrible [SEP] the smell is overwhelming the worst i have ever encountered in a hair dye i would suggest keeping the windows open and use a fanit is easy to use pretty much the same instructions as any other hair dye i have tried for best results it is important to do the allergy and stand tests as instructed also follow the instructions about not massaging it into the scalp it burns a little if that happensit covers grey well it lightened dark blond hair somewhat and produced an uneven time which is part of the point but which seemed a little erratic for my taste