nasostop nasal drops to treat nasal allergies for adults, nasostop nasal drops to treat congestion contain xylometazoline, which is an anti-decongestant and works by constricting the blood vessels in the nasal passages to eliminate nasal congestion and blockage, hydrochloride and nasal congestion, and treat sinusitis and chronic or seasonal nasal allergies and also help in getting rid of the symptoms of hay fever.