Cold and flu season has started and for many that means sinus problems: stuffy nose, runny nose, breathing difficulty or post-nasal drip.  One of the most useful herbs for treating sinus conditions is Eucalyptus.  
    Eucalyptus is not a single plant, but an entire genus of trees and shrubs found primarily in Australia.  Most are evergreen.  Some are better than others for helping the sinuses, but I wouldn't be too concerned about that unless your planning to go to Australia and pick your own.  The bottled oil and tincture you can get at natural and health stores is the right kind.
    In addition to aiding the sinuses, Eucalyptus has other benefits.  The oil of some trees make a reasonably effective natural insect repellent.  It is also a disinfectant.  Many cough drops and over-the-counter treatments for colds and flu contain eucalyptus oil.  It's warming properties result in it being used as a rub for arthritis or other sore joint or sore muscle problems.  It heals some fungal infections.  Some add it to hot tubs to kill bacteria.  Spraying or dabbing the oil on insect bites relieves pain and itching.  A few drops added to water makes an effective mouthwash.
    One of the most surprising uses is for diabetes.  Some animal studies have backed up the belief in that it increased insulin production and reduced blood sugar levels.
    It also has a number of non-medicinal uses.  It helps remove glue and some other sticky substances.  Add a few drops to a batch of laundry to give it a nice fresh smell.  It can remove many stains from carpets and fabric.  
    One use that I find fascinating is that real Aborigine digeredoos are made from the branches of eucalyptus trees that have been hollowed out by termites.  I think that makes it the only musical instrument essentially made by insects.