Rotten Flesh

Rotten Flesh is an item from the 1.8 update dropped from zombies; eating it restores some of your hunger meter however there is a chance that after eating it your hunger meter will deplete at a faster rate. ). As of the pre-release testing, poisoning causes no damage by itself, but does sometimes cause the player to be unable to eat. It is unclear whether poisoning causes creatures to do increased damage to the player or not. As of the 1.8 Pre-release, the poison effect causes a player to take half as much damage (it is unclear if this is a bug or an intended effect). Rotten flesh cannot be cooked.

Rotten flesh heals Wolves without poisoning or causing damage to them. This can be useful because you won't have to heal by wasting your food and giving them something that has nothing of use to you.

Unconfirmed
When eating rotten flesh (everyday) Me and a friend always wake up with monsters hugging us. Lit up room.