Shama-il Tirmidhi
Shama-il Tirmidhi Chapter 006, Hadith Number 003 (046).
Hadith Section/Book: Shama-il Tirmidhi Chapter 06. Rasoolullah Using a Dye
Jah-dhamah Radiallahu 'Anha, the wife of Bashir Kha-saasiyyah Radiallahu 'Anhu says: "I saw Rasulullah Sallallahu 'Alayhi Wasallam coming out of the house after taking a bath and was stroking (or combing) his hair. There were signs of henna on his mubaarak head."