Free Lemonade in The Binding of Isaac is an active item that creates a big puddle of lemonade under Isaac, similar to the Lemon Party pill. That puddle damages enemies that stand in it, dealing 8 damage per tick, and it lasts about 19 seconds.

What it does

  • Spawns a lemonade creep pool under Isaac.
  • Damages enemies over time if they touch or stand in it.
  • Works especially well when you can lure enemies into the puddle.

Extra note

There’s also a mod item called Lemon Juice in a Fiend Folio mod, but that is separate from the base-game lemonade item and affects tear size instead.

TL;DR: it’s a damage puddle active item, best used by dropping it where enemies are forced to walk.