What to give for BAD allergies/cold symptoms

[Guest guest]

Has anyone used a natural or rx. drug that WORKS in relieving allergy/cold symptoms? I have a 6 yr. old ASD daughter who is plagued with allergies from spring through most of fall. I know she is allergic to something on or around our property but I'm not sure what. My guess would be some type of tree. We are the last house on a dead end street, nearly an acre treed lot, surrounded by a marsh and woodsy area on two sides. So, the allergies could be coming from ANYTHING or a multiple of things. Moving is NOT an option for us right now. Any suggestions or advice would be appreciated.

Karmen