Generally speaking, red dyes can cause irritation on the eyes, and blue may cause a reaction on the lips. This is why so many red/bright pink pigments are not recommended for use on the eyes, and why many blue/purple pigments are not recommended for use on the lips. That being said, many people use pigments in the "not recommended" ways anyway. It's really just a matter of what you're comfortable with. If you've never had a reaction to red dyes and want to try Magenta Madness on your eyes, go for it. But I would suggest doing it when you don't have to be anyplace for an extended period of time that day, so that if you DO have a reaction, you can remove the product immediately. MAC really doesn't educate their customers or their artists in pigment safety, so you kind of have to take the initiative yourself. All "not recommended for eye/lip use" really means is that the product hasn't necessarily been tested for use in the way that is not recommended, so if you do have a reaction to it, MAC takes no responsibility for it. Personally, I don't use any product in a way that is not recommended...but sometimes it is tempting, lol. Probably went off on a bit of a tangent there responding to your red dyes comment, but HTH!