It's sneezin' time again because it's springtime and several kinds of flora insist on blooming. It's not the lovely fragrant plants that cause all the trouble, either. The pollen on those ones is big and clunky enough that the immune system can deal with it quite handily. No, it's the invisibly-small windborne pollen from off of trees and grasses that does all the mischief. Thank Unnamed Deity for cromoglycate nasal spray, that's all I gotta say.