1. It is permissible for men and women to dye the hair. However it is impermissible to use black dye to dye the hair.
عن ابن عباس قال قال رسول الله صلى الله عليه وسلم: يكون قوم يخضبون فى آخر الزمان بالسواد كحواصل الحمام لا يريحون رائحة الجنة. (ابو داود رقم 4214)
Hadhrat ibn Abbaas (Radhiyallahu Anhuma) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “A group will appear close to Qiyaamah who will dye their hair with black like the bellies of pigeons. They will not be blessed with the fragrance of Jannah (i.e. for some period they will undergo punishment in Jahannum and be deprived of Jannah).”
عن جابر بن عبد الله قال أتى بأبى قحافة يوم فتح مكة ورأسه ولحيته كالثغامة بياضا فقال رسول الله صلى الله عليه وسلم غيروا هذا بشىء واجتنبوا السواد. (ابو داود رقم 4206)
Hadhrat Jaabir (Radhiyallahu Anhu) reports that Hadhrat Abu Quhaafa (Radhiyallahu Anhu) (the father of Hadhrat Abu Bakr [Radhiyallahu Anhu]) was brought before Rasulullah (Sallallahu Alaihi Wasallam) on the occasion of the conquest of Makkah Mukarramah. His hair and beard was completely white which resembled the Thaghaama plant (a type of plant which its fruit and flowers were white in colour). Rasulullah (Sallallahu Alaihi Wasallam) said to him: “Change the colour of this (whiteness) through dying it with something, however abstain from black dye.”