Do your lice hurt your

Narrated Ka`b bin Ujrah:

The Prophet (s.a.w.) came to me during the period of Al-Hudaibiya, while I was lighting fire underneath a cooking pot and lice were falling down my head. He (p.b.u.h) said, "Do your lice hurt your?" I said, "Yes." He said, "Shave your head and fast for three days or feed six poor persons or slaughter a sheep as a sacrifice:"

[Sahih al-Bukhari (Medicine / Kitab-ul-Tib)]

{ English reference : Vol. 7, Book 71, Hadith 604
Arabic reference : Book 76, Hadith 5765 }