Sahih Muslim Book 21, Hadith Number 4773.

Chapter : The eating of the flesh of domestic asses is unlawful.

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.