Chlorpheniramine is an antihistamine commonly used to relieve allergy symptoms such as sneezing, runny nose, and itchy eyes. It works by blocking the action of histamine, a substance in the body that causes allergic reactions. Chlorpheniramine is often found in over-the-counter medications for colds and allergies. This medication is available in various forms, including tablets and liquid. While effective, it may cause side effects like drowsiness, dry mouth, and dizziness. It is important to follow dosage instructions and consult a healthcare professional if you have any concerns or pre-existing conditions.