Cheek Pouch is a Pokémon ability introduced in the sixth generation. It restores health when consuming a berry.
Cheek Pouch restores 33% of the Pokémon's maximum HP after the berry's effect takes place. Consuming the berry for other methods like using Fling, Natural Gift and directly from the Bag will not activate Cheek Pouch. Cheek Pouch will also activate if the Pokémon consumes another Pokémon's berry via Bug Bite, Pluck or Fling.
Cheek Pouch does not work under the effect of Heal Block
Pokémon Mystery Dungeon
On top of healing when eating seeds or berries, an enemy Pokémon will also hold a Seed with it when it is spawned on the floor with this ability even if there was none for it to pick up. It can still use those seeds too.