Sahih Bukhari Volume 007, Book 067, Hadith Number 436.
Narrated By Anas bin Malik : Someone came to Allah's Apostle and said, "The donkeys have been (slaughtered and) eaten. Another man came and said, "The donkeys have been destroyed." On that the Prophet ordered a caller to announce to the people: Allah and His Apostle forbid you to eat the meat of donkeys, for it is impure.' Thus the pots were turned upside down while the (donkeys') meat was boiling in them.