I have heard that it is unlawful for men to colour their hair black. They can, however, colour their hair using 'hina'. I don't understand why one is allowed and the other is not. Please also tell me about a young man of about 20-25 who has got his hair white due to some medical reasons. Can he colour his hair black? What about ladies?
Colouring one's hair is a matter which has not been touched by the Shari`ah. It is a matter of our own personal taste. Men or women, whether young or old, have every right to decide in this regard. They can colour their hair black or use `hina’ -- whatever they prefer.
The Ahādīth from which certain people have deduced that colouring one's hair black is prohibited, I am afraid, have been misinterpreted. They do not forbid colouring the hair black; they just describe one feature of a certain group of people near the Day of Judgement who will go to Hell (the reasons of which are not stated). This feature which is merely a sign from which they can be recognized is that they will colour their hair black. In other words, the Ahādīth do not say that the reason because of which these people will be consigned to Hell is the fact that they used to colour their hair black. They only state that a certain lot of people, who can be recognized by their hair coloured jet black, will not enter Heaven. Obviously, they will meet this fate because of reasons which make them worthy of this punishment.