Reactine Extra Strength Antihistamine Tablets relieves indoor and outdoor allergy symptoms. Allergy symptoms kick in when your immune system overreacts to substances called allergens. Reactine contains 10-milligrams of Antihistamine Cetirizine Hydrochloride to provide fast 24-hour relief of itchy, watery eyes, nasal congestion/stuffiness, itchy nose and throat, sneezing, runny nose caused by seasonal and perennial allergies, and itching due to allergic skin reactions, such as hives. Understanding and recognizing the symptoms is half the battle. Your body releases many chemicals, one of which is called histamine. Histamine is the most abundantly released chemical and is responsible for causing most of your symptoms. Indoor allergens, including mold, dust, and pet dander can cause allergy symptoms at home and at work. Since indoor allergies can be triggered any time of year, they can often be easily confused with a cold. Outdoor pollen from the spring, summer, and fall can be present inside your home too. Speak to your doctor or pharmacist. To be sure this product is right for you, always read and follow the label.