The Bow and Poison Arrows are the unlockable long ranged weapon of the apache and is unlocked by completing arcade mode. It has the same starting damage as the the iron arrows however the poisoning after-affects can consume a large amount of health rather quickly making it a very powerful long-range weapon.
Apaches drained the venom from dead rattlesnakes for their arrows. A very painful poison, it destroys red blood cells and body tissue. It is crippling, and likely fatal.