It was narrated that Anas bin Malik said:
"The Messenger of Allah milked a sheep and drank some of its milk, then he called for water and rinsed his mouth and said: 'It has some greasiness in it.'" (ES)
English reference (ES): Vol. 1, Book 1, Hadith 501 (ES)
Arabic reference (ES): Book 1, Hadith 540 (ES)