"At any time between turns, if the Pokemon this card is attached to is affected by any Special Conditions, remove all of them. Then discard Lum Berry."
Basically, attach it to a Pokemon. If that Pokemon ever becomes Asleep, Confused, Paralyzed, Poisoned, and/or Burned, you can remove the special condition(s) after your opponent ends his/her turn but before you begin yours (or vice viersa) and discard Lum Berry.