hey,
     Orange oil is good for your immune system, and smells good too.
Lavender too, i guess. maybe cause it awakens the scences-used to be used in smelling salts.
tea tree & lavender are great for the skin & can be applied onto skin (with few exeptions-ie eyes,mouth ect)
without carrier oils, so if you put them on you-they wont burn or irretate!

-jessx

I found some recipes in a book writen by a registered nurse named Valerie Cooksley.  She lists Lavender, Bergamot, Lemon, Juniper, Peppermint, Geranium, and Rose oils as helpfull for allergies and hay fever.  we make a Synergy for our Business called Spring Breath that has Blue Tansy in it as well as a combination of some of the oils I mentioned.  I know it worked for me.  Where I live we have cottonwood trees that when they are really going it looks like it's snowing in the spring.  I don't have allergies, but all that pollen was sure affecting me!  I stuck my face in front of a good diffuser and got some powerfull relief, fast.

My mother used to suffer from hay fever until she started chewing the capping wax from honey comb. Since then the hay fever is almost gone. For sinus suffers try magnet therapy, I know of some really good results. And of course eucalyptus and cyprus oils are great for sinus relief too.