Sahih Bukhari Volume 7, Book 72, Hadith Number 784.

Narrated By IsraiI : Uthman bin ‘Abdullah bin Mauhab said, “My people sent me with a bowl of water to Um Salama.” Isra’il approximated three fingers (‘indicating the small size of the container in which there was some hair of the Prophet. ‘Uthman added, “If any person suffered from evil eye or some other disease, he would send a vessel (containing water) to Um Salama. I looked into the container (that held the hair of the Prophet) and saw a few red hairs in it.”