Costunolide is a sesquiterpene lactone used in pharmacological research for its anti-inflammatory properties, particularly in animal models of rheumatoid arthritis, where it reduces swelling and levels of pro-inflammatory cytokines such as TNF-α and IL-6. It is not yet used clinically and remains in preliminary research stages. Additionally, it acts as an agonist for bitter taste receptors (TAS2Rs), supporting studies on taste perception and physiological responses. It is also investigated for its potential to modulate airway smooth muscle function via TAS2R activation, with possible applications in respiratory conditions like asthma. Furthermore, its effects on gastrointestinal function are being explored due to TAS2R expression in the gut, which may influence digestion and metabolic processes.