Sanity is a red bar on the left side of the screen that represents Alice Liddell's (mental) health.
Alice can absorb Meta-Essence crystals, the life force of everything in Wonderland. The larger the crystal, the more Meta-Essence it contains. Meta-Essence restores both Sanity and Will in equal amounts.
Alice can also collect Sanity Shards. These red crystals can be found strewn about all over Wonderland and can restore a finite amount of Sanity.
Types of shards
Small shard – Restores a small amount of Alice's health.
Large shard – Restores a medium amount of Alice's health.