Tachykinin NK2 receptors are distributed in periphery, in the smooth muscle of the respiratory, gastrointestinal, genitourinary tract, and within the brain. Substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) are endogenous ligands for NK2 receptors and are active in the peripheral and central nervous systems. NK2 antagonists have the potential to reduce airway motor responses and prevent hyperactivity by inhibiting NKA-induced bronchoconstriction in asthmatic patients. Due to its abundance, peripherally and centrally, tachykinin NK2 receptor antagonists have high potential in treating various disease states ranging from asthma to irritable bowel syndrome, to detrusor hyperactivity, to anxiety. This review is an evaluation of NK2 receptor antagonists as possible therapeutics for a myriad of pharmacological treatments.