If you have hayfever, there is a good chance, that you are already familiar with the wide array of pills, nose sprays and eye drops available to manage your hayfever symptoms. The most common medications are so called anti-histamines. To understand how they work you have to understand that hayfever is basically a faulty reaction from your immune system to for example pollen. Anti-histamines work to suppress this reaction of your immune system. There are anti-histamines which work locally - for example as a nose spray - and pills which work systematically across all your symptoms. Older versions of these pills tended to make you really tired, but newer ones don´t - so make sure to get the right ones!