Agastache is a genus of plants found almost worldwide. Different species are used in several native cultures for healing. The best known of these is Agastache rugosa, also called the giant hyssop, wrinkled giant hyssop, Korean mint, or in Chinese huo xiang.

Agastache rugosa is a perennial or biennial plant that grows to a height of 4 ft (1.2 m). It is native to China but has spread to Japan, Korea, Laos, and Russia. It grows wild on sunny hillsides and along roads, but it can be cultivated in backyard gardens.

The highly aromatic leaves and purple or red flowers are used for healing. Several other species of agastache found in other parts of the world are used in healing. These include A. nepetoides (yellow giant hyssop), A. foeniculum (anise hyssop), and A. mexicana.

Leaf and flower color vary considerably among the different species. Many species of agastache also are grown commercially in the United States for landscaping. In southern China and Taiwan, Pogostemon cablin, a relative of Pogostemon patchouli, the Indian plant that produces patchouli oil, is used interchangeably with A. rugosa.

A. rugosa is used extensively in Chinese herbalism. Its first recorded use dates from about 500 A.D. It is associated with the lungs, spleen, and stomach and is classified as having a warm nature and an acrid and aromatic taste.

Traditionally, agastache has been associated the treatment of several different sets of symptoms. It has long been used to treat stomach flu, stomachache, nausea, vomiting, diarrhea, abdominal bloating, and abdominal pain. It is combined with Scutellaria (skullcap) to treat morning sickness in pregnant women.

It is also a component of formulas that improve digestive balance by aiding the absorption of nutrients and intestinal function. In Chinese herbalism, A. rugosa is also used to treat summer flu or summer colds with accompanying low fever, feelings of fullness in the chest, and headache.

It is also used to treat dark urine and a feeling of heaviness in the arms and legs. A lotion containing A. rugosa is applied externally to treat fungal infections. Other cultures independently have discovered similar uses for other species of agastache.

A. mexicana is grown in Mexico and used to treat gastrointestinal upsets, nervous disorders, and cardiovascular ailments. The leaves of A. nepetoides are used by Native Americans to treat skin rashes caused by poison ivy. A. foeniculum leaves have a strong licorice taste (accounting for its English name, anise hyssop).

These leaves can be brewed in a tea to treat coughs, fever, and colds. Rigorous scientific testing of the healing claims made for agastache is scarce. Most of the work that done on this herb involves test-tube studies or animal testing.