Decongestants can ease nasal congestion during a cold by reducing swelling in the nasal lining. They come as tablets, syrups, and nasal sprays and are intended for short-term symptom relief, not to cure the cold.
Decongestant nasal sprays should generally be used for no more than about three to five days, because longer use can cause rebound congestion that makes the blockage worse. Oral decongestants may not be suitable for people with high blood pressure, heart problems, an overactive thyroid, glaucoma, or certain other conditions, and they can interact with some medicines.
Gentler alternatives include saline sprays or rinses and steam inhalation. Ask a pharmacist which option fits you, especially if you are pregnant, have a health condition, or are giving anything to a child, and follow the label exactly.