Best used for sinus, allergies, congestion due to coughs and colds; etc. Eucalyptus oil is used commonly as a decongestant and expectorant for upper respiratory tract infections or inflammations, as well as for various musculoskeletal conditions. Menthol is a compound obtained from peppermint oil or other mint oils. Menthol has local anesthetic and counterirritant qualities. It is contained in nonprescription products for short-term relief of minor sore throat and minor mouth or throat irritation.