equip it on a character with all the 'remedy lore' licenses and have that character throw remedies at an enemy. instant sleep/slow/blind/poison/silence/etc. status for the enemy. it's great for marks, bosses, and rare game. it probably works with phoenix downs, too but i imagine it misses a lot

you can buy it from the clan provisioner in rabanastre for like 30000 gil once you hit the 3rd or 4th rank