A Potion is an item that heals 20 HP of a Pokémon. It has no effect on a fainted Pokémon. A potion can be found in the player's PC at the start of the game, except in Generation IV. It costs 300 Pokémon Dollars at Poké Marts and can be sold for 150 Poké Dollars. It belongs to the Medicine Pocket in the player's bag.
Locations in the Games
R/G/B/Y & FR/LG: Most Poké Marts; One from PokéMart worker on Route 1 (Also 1 in PC).
G/S/C & HG/SS: Most Poké Marts.
R/S/E: Most Poké Marts; 1 from PokéMart worker in Oldale Town (Also 1 in PC).
D/P/Pt: Most Poké Marts; 1 from Poké Mart worker on Route 201.
B/W: Most Poké Marts; 1 from Poké Mart worker on Route 1.