Does toothpaste break the fast?
Short answer
Using toothpaste does not break the fast with care not to swallow any of it, and if something enters unintentionally there is no making up.
Evidence and explanation
The Shaykh determined its permissibility with care not to swallow it.
Scholar referenced
This editorial summary is based on the original source linked below and is not presented as a verbatim quotation from the scholar.
From the text of the answer (Arabic, with an English translation)
Original answer — Shaykh ‘Abd al-‘Aziz ibn Baz
حكم استعمال معجون الأسنان للصائم — فتوى ١١٨٠٧- Question
«هل يجوز للصائم أن يستعمل معجون الأسنان وهو صائم في نهار رمضان؟»
English translation (unreviewed): May a fasting person use toothpaste while fasting in the daytime of Ramadan?
- From the text of the answer
«لا حرج في ذلك مع التحفظ عن ابتلاع شيء منه، كما يشرع استعمال السواك للصائم في أول النهار وآخره، وذهب بعض أهل العلم إلى كراهة السواك بعد الزوال، وهو قول مرجوح، والصواب عدم الكراهة؛ لعموم قول النبي ﷺ: السواك مطهرة للفم مرضاة للرب [١] أخرجه النسائي بإسناد صحيح عن عائشة رضي الله عنها، ولقوله ﷺ: لولا أن اشق على أمتي لأمرتهم بالسواك عند كل صلاة [٢] متفق عليه.»
English translation (unreviewed): There is no harm in that, taking care not to swallow any of it, just as the use of the siwak is prescribed for the fasting person at the beginning and end of the day. Some scholars held that siwak after the sun passes the zenith is disliked, but this is a weaker view, and the correct view is that it is not disliked, because of the general saying of the Prophet ﷺ: “The siwak is a purification for the mouth and pleasing to the Lord” [1], reported by al-Nasa'i with a sound chain from 'A'ishah, may Allah be pleased with her, and his saying ﷺ: “Were it not that I would burden my nation, I would have ordered them to use the siwak at every prayer” [2], agreed upon.
The Arabic excerpts matched the original page word for word by an automated check and have not had human scholarly review. The English translations are unreviewed translations made for this site; they are not an approved Shari‘ah translation. Rely on the Arabic original.
Source
Ruling on a fasting person using toothpaste
Title of the original page (Arabic): حكم استعمال معجون الأسنان للصائم
Shaykh ‘Abd al-‘Aziz ibn Baz, may Allah have mercy on him