Shrinking Solution is, as the name suggests, a potion that causes the drinker to shrink. It is primarily used to transport livestock.
However, the potion does not merely cause shrinking, but also causes the imbiber to become younger (which often also results in a loss of size, if the reversion continues into childhood). As a result, it must be used with great care.
Related drugs: Confusing Concoction, Rat Tonic and Wolfsbane Potion.