What's in a sneeze?

My children especially my 2 sons, and my husband often has the case of the "sniffles" and that is every month since we moved to Cavite. My children's pedia is also baffled, she has cleared my oldest son from primary complex. However she also mentioned that their colds which eventually would lead to cough and fever may be due to an allergic reaction to pollen. As our home is situated in a place that used to be a farm and which is near acres of farm land, my kids were given medicines which they need to maintain to keep them off the allergy. This is of course going to be costly, so i am wondering if there are any home remedies that could cure their allergic reaction. I have in my garden fresh oregano that my children's yaya makes into tea and that has worked so far for ordinary cough. If you have any home remedy suggestions I will appreciate any inputs you can share on this ... :)