Polytussin is a multi-action over-the-counter cough syrup designed to relieve dry cough, nasal congestion, sneezing, and throat irritation linked to colds or allergies. It typically combines a cough suppressant (dextromethorphan), a nasal decongestant (phenylephrine), and an antihistamine (pyrilamine) to target multiple symptoms simultaneously. While generally considered safe when used as directed, possible side effects include drowsiness, dizziness, or dry mouth. Always follow the dosage and check with a healthcare professional if symptoms persist.