STAT6 and airway hyperresponsiveness: 18β-Glycyrrhetinic acid, which is the major bioactive component of Glycyrrhizae Radix, strongly suppressed airway hyperresponsiveness, the accumulation of inflammatory cells and levels of IL-5 and IL-13 in bronchoalveolar lavage fluid (BALF) through inhibition of the orphan receptor γ t (RORγt), signal transducer and activator of transcription 6 (STAT6), GATA-binding protein 3 (GATA-3) pathways and upregulation of the forkhead box p3 (Foxp3) transcription pathway [10].