Objectives: This study was intended to assess the protective mechanism of the effects of hydroalcoholic extract of the leaf of Juglans regia L. against airway inflammation and pulmonary edema by measuring the expression levels of heme oxygenase-1 (HO-1), occludin, and Zonula occludens-1 (ZO-1) in the lung tissues. The gene discussed is TJP1; the disease is pulmonary edema.