Maekmoondong-tang (MMDT) has long been used in Asian countries to treat respiratory diseases. However, the precise mechanisms underlying its effects on asthma are unknown. This study was conducted to evaluate the protective effects of MMDT in a cockroach allergen (CKA-)induced animal model of allergic asthma. After being challenged with CKA, the number of macrophages, eosinophils, neutrophils, lymphocytes, and total cells in the bronchoalveolar lavage fluid (BALF) was evaluated. The Th2 specific cytokines IL-4, IL-5, and IL-13 were also analyzed in BALF along with IgE levels in serum. For histological analysis, hematoxylin and eosin (H&E) staining, periodic acid-Schiff (PAS) staining, and immunohistochemical staining were performed. In addition, airway hyperresponsiveness was assessed by noninvasive plethysmography. The cellular profiles and histopathologic analysis demonstrated that peribronchial and perivascular inflammatory cell infiltrates were significantly decreased in the MMDT-treated groups compared with the cockroach extract-injected (CKA) groups. In addition, the IgE, IL-4, IL-5, and IL-13 levels were significantly decreased in the MMDT group. MMDT treatment also significantly attenuated airway hyperresponsiveness. These results demonstrated that MMDT significantly reduced the hallmark signs of asthma: elevated serum IgE, airway eosinophilia, airway remodeling, mucus hypersecretion, and airway hyperresponsiveness. The remarkable antiasthmatic effects of MMDT suggest its therapeutic potential in allergic asthma treatment.