The Secret Potion is the name of a type of potion used in Pokémon: Gold, Pokémon: Silver, Pokémon: Crystal, Pokémon: Diamond and Pearl, Pokémon: Platinum, Pokémon: HeartGold and Pokémon: SoulSilver. It is a Key Item, as it is essential to passing through the games it appears in.
The Player can't actually use it. It must be delivered to the character that requests it( in the case of Diamond, Pearl, and Platinum, Cynthia). It can apparently heal any injury, as it healed Jasmine's Ampharos HP wise, and also the confusion( portrayed as a headache) contracted by the Psyduck Cynthia needed healed, even though the statuses healed were different.
-Even though it is a potion, it cannot be used by the player.
- Apparently, it can heal any ailment, similarly to a Full Restore.