Antihistamines are medications that help relieve allergy symptoms by blocking the action of histamine, a substance in the body that causes allergic reactions. When you encounter allergens like pollen or pet dander, your body releases histamine, leading to symptoms such as sneezing, itching, and runny nose. Antihistamines can be taken in various forms, including tablets, liquids, and nasal sprays. There are two main types of antihistamines: first-generation and second-generation. First-generation antihistamines, like diphenhydramine, can cause drowsiness, while second-generation antihistamines, such as loratadine, are less likely to make you sleepy. Both types are effective in managing allergy symptoms, but it's important to choose the right one