From the Manufacturer:
The tea is stomachic, diaphoretic, carminative, stimulating, and expectorant. Along with horehound, it is used for lung ailments including bronchitis and asthma. A gargle made from the leaves relieves sore throats. Externally, a tea, poultice, or strong bath of the leaves is used to relieve muscular rheumatism. One-fourth ounce of the herb to a pint of boiling water makes a medicinal infusion.
The essential oil contains pinocamphone, isopinocamphone, pinenes, camphene and other substances. The plant also contains up to 8 percent tannin, and a glucoside-hyssopin. Extracts of hyssop have shown antiviral effects against herpes simplex. The oil is used to make chartreuse and eau-de-cologne.