Busting open slurp barrels will replenish health by 10, that is unless it’s at 100, in which case it adds 10 shields instead.
You can acquire shields with several different items. Regular shield potions give 50 extra shield points, up to a maximum of 100. Small shield potions give 25, up to a maximum of 50. Busting open slurp barrels will replenish health by 10, that is unless it’s at 100, in which case it adds 10 shields instead. Various fish can heal shields and health, too, so use a fishing rod to catch them in a pinch.