Antihistamines are a class of medications commonly used to manage symptoms of allergies. These drugs function by inhibiting the action of histamine, a chemical secreted by the body during an allergic reaction. Histamine contributes to symptoms such as itching, sneezing, runny nose, and watery eyes. By inhibiting histamine's effects, antihistamines help alleviate these uncomfortable symptoms, providing relief to people suffering from allergic reactions, hay fever, or even the common cold.