Qianghuo (the rhizomes and radixes of Notopterygium incisum Ting ex H.T. chang) is a traditional Chinese medicine, and widely used as an anti-inflammatory, anodyne, antifebrile agent. Qianghuo volatile oil also exhibits the same properties, and the effects are probably related to the inhibition of cyclooxygenase (COX), but its bioactive components are not clear yet. To figure out the bioactive components of Qianghuo volatile oil target to cyclooxygenase-2 (COX-2), a ligand fishing method using immobilized COX-2 magnetic beads (COX-2-MB