Dungeon Master Guide[]
After drinking this potion, the individual (and everything carried or worn) diminishes in size to as small as 5% of normal. The percentage of the potion consumed determines the amount a character shrinks. For example, if 40% of the contents are swallowed, the person shrinks to 60% of normal size. The effects of this potion last for six turns plus 1d4+1 turns.
Encyclopedia Magica[]
After drinking this potion, the individual (and everything carried or worn) diminishes in size to as small as 5% of normal. The percentage of the potion consumed determines the amount a character shrinks. For example, if 40% of the contents are swallowed, the person shrinks to 60% of normal size. The effects of this potion last for six turns plus 1d4+1 turns.