Which medication is an antihistamine used for allergy relief?

Benadryl is an antihistamine commonly used for allergy relief. It contains diphenhydramine, which works by blocking the action of histamine, a substance in the body that causes allergic symptoms. When someone is exposed to allergens, the immune system reacts by releasing histamines, leading to symptoms such as itching, sneezing, runny nose, and watery eyes. By inhibiting this action, Benadryl effectively alleviates those symptoms, making it a popular choice for treating allergic reactions.

The other medications listed serve different purposes. Ventolin HFA is a bronchodilator used to relieve symptoms of asthma and other conditions related to breathing. Flovent is a corticosteroid used to prevent asthma attacks by reducing inflammation in the airways. Dulcolax is a laxative used to treat constipation. Therefore, Benadryl stands out as the only option specifically indicated for allergy relief among the choices provided.