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.'" (FR)
English reference (FR): Vol. 1, Book 1, Hadith 501 (FR)
Arabic reference (FR): Book 1, Hadith 540 (FR)