From the Manufacturer:
Traditionally, Hyssop was used as a natural cold and flu remedy. Hyssop is also great for lung congestion, fevers, digestion and blood pressure regulation. Hyssop can also be used externally for wounds, burns, bruises and infections.
Its main use is for respiratory disorders - colds, flu, bronchitis, upper respiratory catarrh. It contains the bitter component, marrubiin (also found in White Horehound), which has expectorant properties. It may be used for fevers, as it promotes sweating. It has also been used for sluggish digestion, mucus congestion in the intestines, and for throat infections. It can be useful for the cold sores of the Herpes simplex virus due to its antiviral activities. Externally, it is beneficial for burns, bruises, wounds, and infections.