This is a terrible admission, but the scent of perfume made me horribly sick to my stomach while I was ill. Great situation for a perfumer to be in. However, I agree with everyone here: the scent of mints and eucalyptus are soothing, and will help with any congestion you may be experiencing. Teas made of peppermint and ginger should help quell nausea, as will chewing ginger root or any natural crystallized ginger candies.
Be careful of the perfumes [or any other strong scent!] you expose yourself to when you're sick. The smell may stick subconsciously, and may trigger a negative reaction later on once you're well.
After this past illness, it'll be a long time before I can stand the smell of V8 or any other tomato juice. I'm sure you all don't want to hear the gory details on that. =P