Eucalyptus: 100% Pure Joy Naturals essential oil is a go-to remedy for colds and the flu. Eucalyptus essential oil can be used to calm a cough in several ways. A person may want to try: adding a few drops of eucalyptus oil to 1 ounce of carrier oil and rubbing the mixture onto the chest and throat or diluting eucalyptus oil in boiling water and inhaling the steam. It is also a wonderful treatment for sore muscles, a key ingredient in nontoxic household cleaners and much more. Botanical Name: Eucalyptus radiata. Plant Part: Woods and Leaves. Origin: Australia.