Levocetirizine HCl 5 mg is a second-generation antihistamine commonly used to treat symptoms of allergic rhinitis (such as sneezing, runny nose, itchy or watery eyes) and chronic urticaria (hives) with itching and rash. It works by blocking histamine receptors (H1 receptors), preventing the action of histamine, a substance that causes allergy symptoms. Levocetirizine is known for its high efficacy and low sedative effect, making it suitable for long-term use, including during the day, without significantly impairing alertness or causing drowsiness.