I've stopped using traditional hair colour products for a few reasons, but one of the primary ones was that I would often feel dizzy and nauseous after using a dark shade. I recently used a mixture of black and brown Manic Panic and it didn't cause any kind of reaction. Of course, within a week, it had washed out. I'll get around to doing my hair again soon...maybe this weekend. I don't mind the "hassle" of colouring temporarily, though. I figure it's safer than what I was doing before. I don't know if this is helpful to the original poster, but it's a suggestion as an alternative. There's also henna + indigo for dark hair, but some people don't like the mess or the fact that it's generally a very permanent option.