TGFB1 and pemphigus foliaceus: This study aimed to investigate the potential antifibrotic effects of <i>Thymus syriacus</i> essential oil (TS) on the TGF-β/SMAD pathway in bleomycin-induced PF.<h4>Methods</h4>PF was induced with bleomycin, and TS was administered at concentrations of 50 and 100 mg/mL for 28 days.