Ground Ivy (Glechoma hederacea)

For many people the scent of eucalyptus conjures up days spent in bed during childhood with eucalyptus and other oils smothered on the chest. Eucalyptus is a common ingredient in many over-the-counter cold remedies.

Garlic (Allium sativum) is a bulbous perennial in the onion family, recognized for its sharp flavor and characteristic odor. It is widely used in cooking, and crushed fresh garlic contains allicin. NCCIH says garlic supplements may lower cholesterol, blood pressure and blood sugar to a small extent, but very little research has tested claims that they boost immunity.

Gentian (Gentiana lutea) is a robust, upright perennial growing to about 4 ft (1.2 m), with bright yellow, star-shaped flowers and oval leaves. Known for its exceptionally bitter constituents (particularly gentiopicroside and amarogentin), gentian has long been a key ingredient in aperitifs and digestifs.

Goldenseal (Hydrastis canadensis) is a low-growing North American perennial, recognized by its thick yellow root and a short erect stem up to about 1 ft (30 cm). Native Americans historically used goldenseal for digestive disorders, wounds, skin and eye conditions, and cancer, and NCCIH says it is promoted today for colds and other upper respiratory infections, hay fever, diarrhea and constipation. NCCIH says there is not enough evidence to know whether goldenseal helps any health condition.

Horseradish (Armoracia rusticana) is a robust perennial with a thick, pungent taproot, large crinkled leaves, and clusters of white flowers. It is known for its strongly spicy flavor.

Pau d'arco is an evergreen tree that can reach 100 feet in height, producing pink flowers. The bark of this South American tree is used as a tea in traditional medicine for a wide range of ailments; MSK says its antibacterial and anticancer effects in laboratory studies have not been shown in humans. The tree grows in both mountainous terrains high in the Andes and in low-lying areas of Paraguay and Brazil. The prized inner bark is collected from wild-growing trees throughout the year.

Triphala is not a single herb but a traditional Ayurvedic blend of three fruits: haritaki (Terminalia chebula), bibhitaki (Terminalia bellirica), and amalaki or Indian gooseberry (Emblica officinalis). Haritaki is described in Ayurveda as having five flavors (bitter, sour, astringent, salty, and sweet). Bibhitaki is described as pungent and warming. Amalaki is also described as having five flavors (sour, astringent, sweet, pungent, and bitter) and contains small amounts of anthraquinones.