Nasacort Allergy Nasal Spray is a once-a-day hayfever treatment. It is available from your chemist without a prescription. Nasacort Allergy helps control and relieve hayfever symptoms, like sneezing, itching and a runny or blocked nose. It contains triamcinolone acetonide, which prevents the body from releasing the chemicals that cause the symptoms of hayfever. Some people start to get relief on the first day of treatment, though it may take up to 3 or 4 days to reach maximum effectiveness.