Heaves, clinically known as recurrent airway obstruction (RAO), is a common respiratory condition in horses, particularly affecting older animals. Characterized by cough, nasal discharge, and difficulty in breathing, heaves can significantly impair a horse's quality of life and athletic performance. The primary cause of heaves is an allergic reaction to environmental allergens, including dust, mold, and pollen. Managing this condition effectively requires a thorough understanding of its pathophysiology and the potential treatment options available, including antihistamines.