How do hay fever tablets work?

Dr Sarah Jarvis MBE If your hay fever symptoms are not controlled on the medication that you are taking after 2-4 weeks, you should discuss this with your doctor. You may need to try a different treatment or add in another treatment. If you are taking hay fever medication regularly and your hay fever is well controlled on your current treatment, you should continue this treatment until the end of the pollen season. https://patient.info/health/hay-fever-leaflet#nav-5