Tirmidhi 725

Its chain is daif. Abu Dawud narrated it in the Book of Fasting, chapter on the tooth-stick for the fasting person, hadith 2364, from the hadith of Sufyan Thawri, through the same chain. Asim bin Ubaydullah is daif due to weakness in his memory, and Ibn Khuzayma criticized this narration, hadith 2007. There is also a report on this subject from Ayesha [Ibn Majah, hadith 1677] and Bayhaqi, 4/272. Ibn Umar used to see no harm in using the tooth-stick while fasting.