Revive

A Revive is an item which revives a fainted Pokémon and restores half of its HP.

Details
Select this item from the Items menu to use it. A list of fainted Pokémon will appear. Tap the desired Pokémon to use the item on it.

In-game description
''A medicine that can revive fainted Pokémon. It also fully restores half of a fainted Pokémon's maximum HP.''

Trivia

 * Becomes available from PokéStops at Level 5.