Abu Dawud
Purification (Kitab Al-Taharah)
Book Number: 001 / Hadith Number: 55
Narated By 'Aisha, Ummul Mu'minin : Ablution water and tooth-stick were placed by the side of the Prophet (pbuh). When he got up during the night (for prayer), he relieved himself, then he used the tooth-stick.