مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 307
Purification
Circumstances which make ablution necessary - Section 1
وَعَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ قَالَ: إِنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ شَرِبَ لَبَنًا فَمَضْمَضَ وَقَالَ: «إِنَّ لَهُ دسما»
‘Abdallah b. ‘Abbas said that God’s messenger drank some milk and rinsed his mouth saying, “It contains greasiness.” (Bukhari and Muslim.)
Mishkat al-Masabih, 307مُتَّفَقٌ عَلَيْهِ (الألباني)