Sunan an-Nasa'i Book 48, Hadith 48
The Messenger of Allah did not dye his hair; his gray hair were only a little beneath his lower lip and at his temples, and a little on his head.
That he asked Anas: "Did the Messenger of Allah dye his hair? He said: "His gray hair didn't go far, it was only a little at his temples."
The Prophet of Allah disliked ten things: Yellow dye, meaning Khaluq, changing gray hair, dragging one's Izar, wearing gold rings, playing with dice (Ki'ab), (a woman) showing her adornment to people to whom it is not permissible for her to show it, reciting Ruqyah, unless it is with Al-Mu'awidhat (Verses seeking refuge with Allah), hanging amulets, removing to ejaculate in other than the right place, and taking away the milk of an infant boy (by having intercourse with his mother)- but he did not say that this is Haram.