Sahih Muslim
The Book of Games and the Animals which May be Slaughtered and the Aninals that Are to be Eaten (Kitab-us-Said wal-Dhabaih wa ma Yukalu min Al-Hayawan)
Book Number: 021 / Hadith Number: 4773
Bara' b. 'Azib reported: Allah's Messenger (may peace be upon him) commanded us to throw away the flesh of domestic asses whether uncooked or cooked; he then never commanded us to eat that. This hadith has been narrated on the authority of 'Asim with the same chain of transmitters.