Pokémon/Power Points
Power Points (PP), found in the various Pokémon video games, are used to limit the amount of times a Pokémon can perform a certain action (see magic point).
To restore PP, the Pokémon must be healed at a Pokémon Center or must be given the Pokémon item Ether or Elixir (or other items, depending on the version).
The item PP UP can increase the maximum amount of PP a Pokémon's attack can have.
To fully increase the power points of one Pokémon attack in generation III, give the attack in question a power point max (PP MAX for short.)
Even if you run out of Power Points in battle (you must lose the Power Points for every move) your Pokémon still wants to fight for you so it will use a move called struggle which has an attack power of 50, and similar to Take down or Double edge, it will cause you to take 1/4 of the damage you inflicted.
Other in-game info
As described before, a Pokémon's PP determines the amount of times a Pokémon can use an attack. However, an error in the game's programming appeared in the Red/Blue/Yellow games; the power points of an opponent, whether wild or owned by a trainer, seemingly had an unlimited amount for each attack. This was fixed as of Gold and Silver. In Ruby/Sapphire/FireRed/LeafGreen/Emerald, a Pokémon with the pick up ability may occasionally be holding a PP UP after a battle. However, the Pokémon with the pick up ability must be in your active party. Most of the time, the attack will use one Power Point, but if the opponent Pokémon has the pressure ability, (which most legendary Pokémon have,) two points will be reduced if the move in question fares a chance at striking an opponent (the move doesn't necessarily have to do damage however.) Any field move a Pokémon has can be used regardless of how many Power Points that move has left for battle (even if the Pokémon has no power points for the field move left for battle, the move can still be used in the field; this is because when the move is used in the field, power points for the move do not get wasted up.)
The range for PP are as follows:
5, +1, +2, +3 (for attacks like HYDRO PUMP),
10, +2, +4, +6 (for attacks like THUNDER),
15, +3, +6, +9 (for attacks like THUNDERBOLT),
20, +4, +8,+12 (for attacks like STOMP),
25, +5,+10,+15 (for attacks like KARATE CHOP),
30, +6,+12,+18 (for attacks like HARDEN),
35, +7,+14,+21 (for attacks like TACKLE),
40, +7,+14,+21 (for attacks like GROWL)
40, +8,+16,+24 (for attacks like GROWL) (in generation III)
The numbers are listed as original power points, followed by the boost from 1 PP UP, that from 2 PP UP, and that from 3 PP UP.
Items used to influence PP and their effects
Ether: Restores PP by ten for one move.(for example from 5 to 15)
Max Ether: Restores all PP for one move.(for example from 0 to 15)
Elixir: heals all Pokémon attacks by ten (for example from 5 to 15)
Max Elixir: heals all Pokémon attacks completely (for example from 0 to 15)
PP UP: amps up total power points by 1/5 of the original amount (for example from 15 to 18)
PP MAX: same as PP UP but multiplied by three (for example from 15 to 24)
MYSTERYBERRY (Generation II only): Restores PP by 10 points for one move. This may be held by a Pokémon and used automatically when needed.
Leppa Berry (Generation III only): Will restore PP by 10 points for one move. It may be held by a Pokémon and used automatically when needed.
Note: These items will only affect the Pokémon who receives the item.
In the Anime
Some people speculate on whether power points exist in the anime or not. Some people say they do, seeing as how all trainers seem to strategize on which attack to use each turn. Some people say they don't, seeing as how some attacks have been seen being launched more times than they are possible in the games, for example, Lorelei's Lapras can use Thunder more than eight times in FRLG. The true answer, however, remains uncertain.