Hyssop is used in herbal medicine to move excesses of fluids or phlegm. Since the expectorant qualities of the herb depend on its essential oil, always brew hyssop tea in a closed vessel and keep the bottle of hyssop tincture tightly closed.

Japanese research published in 2003 in the Journal of Nutritional Science and Vitaminology suggests that hyssop teas can help lower the sharp increase in blood sugars after eating, common to people who have or who are at risk of developing type 2 diabetes.