Natural health: What can my children take for their hay fever?

And... I've got sensitive teeth ever since I had them cleaned by a dental hygienist, is there anything I can do about this?

Megan Sheppard: "Surprisingly simple, yet effective, methods for tackling hayfever include having your children shower and change their clothes after being outdoors, and keeping the windows closed on windy days or during times of high pollen."

My children, aged seven and 10, suffer from hay fever. It is worse during spring and summer. Is there a natural treatment suitable for their age group?