I fixed my hey fever allergy a long time ago using vitamin C.

There is a special kind you need to consume:

Vitamin C 1000mg "slow", "timed" or "delayed" release.

Make sure it has one of the above otherwise it won't be that effective.

You need to take one pill a day for a long time (months) in order for it to get properly absorbed in the body.

This will not only help your allergies, it will prevent you getting colds and flu's (and probably other things as well).