Butterfly Energy are purple butterfly-shaped units of health that serve as the player's life bar. Each world plus the main hub world has one making there six butterflies to find for a max total of twelve (thirteen with the Wellard Tonic). The format display contains six units in each row. If any health is lost, it can be restored by Slurp Shotting butterflies. The maximum Butterfly Energy can be increased by collecting Butterfly Boosters which can be found in each world. The duo starts out with six units of Butterfly Energy.
The duo can also extend their life bar by equipping the Wellard tonic, or reduce it with the Butterthree tonic. The player can additionally make eating a butterfly gain 2 hearts with the Bruiser tonic.