The Dragon Missile.

Lo Lieh stars as Sima Jun, a killer working for a corrupt lord whose orders are followed without question or hesitation. When the lord suffers from a life-threatening boil on his back, he is told by the Imperial doctor that an herb called "Longevity Rattan" offers the only cure and is grown in a remote village by an herbalist named Tan. Lo is sent on a mission to get the herb and bring it back before it's too late.