Mastowell M Tablet is a combination medication containing Bilastine 20 mg and Montelukast 10 mg, formulated for the effective management of allergic conditions. Bilastine is a second-generation antihistamine that selectively antagonizes peripheral H1 histamine receptors, providing relief from symptoms such as sneezing, nasal congestion, rhinorrhea, and pruritus associated with allergic rhinitis and chronic urticaria. Montelukast is a leukotriene receptor antagonist that inhibits the cysteinyl leukotriene receptor, thereby reducing inflammation, bronchoconstriction, and mucus production commonly observed in asthma and allergic rhinitis. The synergistic action of these two agents offers comprehensive control of both upper and lower airway allergic manifestations. Mastowell M is indicated for the treatment of seasonal and perennial allergic rhinitis, chronic idiopathic urticaria, and as adjunctive therapy in asthma management to improve symptom control and reduce exacerbations. The combination enhances patient compliance by reducing pill burden while maintaining efficacy and safety. It is generally well-tolerated, with a low incidence of sedation and minimal adverse effects. Mastowell M should be used under medical supervision, with caution in patients with hepatic or renal impairment, and is not recommended for use in children below the age specified by the prescribing information.