Shroom Shake
From Paper Wiki
The Shroom shake is an item from Super Paper Mario, that replenishes 10 HP, as well as curing poison. This item is stored in a can, so that it can be preserved, unlike a Mushroom, which replenishes 10 HP, just by touching it. The Shroom shake is one of the most basic items of the game, and is sold/located in many places of the game. You can buy The Shroom shake from Howzit