لَا. وَ لَا بَأْسَ بِالْمَضْمَضَةِ وَ الِاسْتِنْشَاقِ لِلصَّائِمِ فَإِذَا تَمَضْمَضَ وَ اسْتَنْشَقَ فَلَا يَبْلَعْ رِيقَهُ
Hadith.1866 - Al-Ala narrated from Muhammad ibn Muslim, from Abu Ja'far (as), that he was asked about regurgitation (qalas): "Does it invalidate the fast?" Imam (as) said: "No."