Antihistamines are pharmaceutical agents designed to alleviate allergy symptoms by blocking the action of histamine, a chemical released during allergic reactions. Commonly used to treat conditions like hay fever, hives, and allergic rhinitis, these medications can reduce itching, sneezing, and runny nose. They come in various forms, including tablets, liquids, and nasal sprays, with some also offering sedation for sleep aid. Their effectiveness and availability make antihistamines a key component in managing allergic responses and improving quality of life.