Irish Moss (Chondrus crispus)

Bacopa, also known as Water Hyssop or Brahmi, is a creeping succulent perennial that can grow to about 20 inches. It features spatula-shaped fleshy leaves and pale blue or white flowers on slender stalks. It thrives in marshlands and along the edges of mangrove swamps in warmer temperate and tropical climates, especially southern Asia, where it forms dense mats on mudflats.

Boldo is a strongly aromatic multi-branched evergreen shrub or tree growing to 20 feet. It has egg-shaped leathery leaves with a lemony scent, clusters of white or yellow bell-shaped flowers, and small yellow berries. Native to Chile and Peru, it has become naturalized in the Mediterranean region and the West Coast of North America, where it grows on dry sunny slopes and in mountain pastures in the Andes. It is widely cultivated, and its leaves are gathered throughout the year.

Goldenrod is a perennial plant growing to 28 inches with toothed leaves and branched spikes of golden-yellow flowers. Native to Europe and Asia and naturalized in North America, it prefers open areas and hillsides and is gathered in summer while in flower. The herbalist John Gerard commented wryly in 1597 about how goldenrod's value plummeted once it was discovered growing locally in Hampstead wood, London, noting society's tendency to esteem things only while they remain rare and foreign. Four hundred years later, this observation still rings true.

Lungwort is a perennial herb growing to 1 foot with broad oval basal leaves, smaller upper leaves mottled with white spots, and clusters of pink-purple flowers. Native to Europe and the Caucasus, it flourishes in mountain pastures and damp sites. The leaves are gathered in late spring. According to the medieval Doctrine of Signatures, which held that a plant's appearance pointed to the ailment it treated, lungwort got its name because its leaves were said to resemble lung tissue. This folk belief is not scientifically founded.

Osha has been overharvested in the wild and is extremely difficult to cultivate. It is listed on the United Plant Savers at-risk list. Until wild populations stabilize, its use should be limited.

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.

Psyllium, also known as flea seed due to its small brown appearance, is produced by several Plantago species. It has long been used as a laxative, and MedlinePlus lists it as a bulk-forming laxative used to treat constipation. The seeds and husks have a bland taste and develop a jellylike consistency when moistened due to their high mucilage content. The plants are extensively cultivated, especially in India, and propagated from seed in spring. Seeds are harvested when ripe in late summer and early autumn.

Slippery elm (Ulmus rubra) is a large tree native to the eastern U.S. and Canada. The medicinal part is the inner bark, prized for its high mucilage content. When soaked in water, it turns “slippery”; this mucilage is traditionally used to soothe the throat and digestive tract, and MSK says slippery elm may help relieve minor cough or sore throat, but there is no evidence it can treat infections or other serious medical conditions.