Mental Herb is an item in the “Held items” category (Items). It costs ₽4000.
In-game descriptions
| Ruby / Sapphire · Emerald | A hold item that snaps POKéMON out of infatuation. |
|---|---|
| FireRed / LeafGreen | An item to be held by a POKéMON. It snaps the holder out of infatuation. It can be used once. |
| Diamond / Pearl · Platinum · HeartGold / SoulSilver · Black / White · Black 2 / White 2 · X / Y | An item to be held by a Pokémon. It snaps the holder out of infatuation. It can be used only once. |
| Sun / Moon · Ultra Sun / Ultra Moon · Let’s Go, Pikachu! / Let’s Go, Eevee! · Sword / Shield | An item to be held by a Pokémon. The holder shakes off move-binding effects to move freely. It can be used only once. |
Where to find it
Not placed on the atlas maps (so far: Red/Blue and Generation 3).
Sources : PokeAPI (items, item_flavor_text, machines) · atlas · pokeemerald species_info.h