This document summarizes information about antihistamines, antitussives, and decongestants. Antihistamines are used for allergy symptoms like runny nose and sneezing. They work by blocking histamine receptors. Antitussives suppress coughs, and come in liquid and cough drop forms. Decongestants reduce nasal congestion by narrowing blood vessels in the nasal passages. All of these medicines come in over-the-counter forms like tablets, liquids, and sprays. They can cause side effects like drowsiness and increased blood pressure if not used as directed.