Deku Sticks are recurring items in The Legend of Zelda series. They were first introduced in The Legend of Zelda: Ocarina of Time as a collectible weapon item, in which Link could carry up to 10 (without upgrades). They were mostly found in the corpses of the enemies known as Deku Babas (the same enemies that drop Deku Nuts). While the stick is very fragile and breaks upon impact of a hard surface, it can be used as a "torch" by having it touch an open flame and does double the damage of the Kokiri Sword.
Link can upgrade the amount of Deku Sticks he can carry at any given time, twice, by finding the vendors in the Lost Woods. Link can use a Deku Stick to turn a butterfly into a fairy.