Stone Root (Collinsonia canadensis)

Marshmallow (Althaea officinalis) is a downy perennial up to about 7 ft (2.2 m), with thick white roots, heart-shaped leaves, and pink flowers. It is known for its high mucilage content.

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.

Cat's claw is a climbing vine that can grow to 100 feet or more, with stems up to 8 inches in diameter, large glossy leaves, and sharp hooks resembling a cat's claws. Native to tropical rainforests in the central and eastern Andes, especially Peru, Ecuador, and Colombia, it has also been found in Guatemala, Costa Rica, and Panama. Indigenous people of the Amazon rainforest have used cat's claw for centuries to ward off disease, and NCCIH says it is promoted today for osteoarthritis, rheumatoid arthritis, cancer and viral infections. NCCIH says there is no conclusive evidence from studies in people to support cat's claw for any health purpose. By the early 1990s, over-collection from the wild threatened the species' survival; only sustainably sourced stem bark should be used, rather than root bark.

Horse chestnut (Aesculus hippocastanum) is a large, stately deciduous tree growing up to about 80 ft (25 m), known for its palmate leaves and prickly green seed pods that contain shiny brown seeds (“conkers”). The seed extract was traditionally used for hemorrhoids, swelling and pain, and is now promoted for chronic venous insufficiency. NCCIH says a review suggested seed extract can improve symptoms of chronic venous insufficiency, but more rigorous trials are needed.

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.

Andrographis, commonly known as Green Chiretta or King of Bitters, is an upright annual herb reaching approximately 3 feet in height. Native to India and cultivated throughout northern regions of India and China, this bitter medicinal plant has been valued in Ayurvedic and traditional Chinese medicine for centuries. MSK notes that it has been studied mostly for colds, flu and upper respiratory infections. The plant thrives on plains and in forest undergrowth, where its spotted pale brown or purple flowers and long seed capsules distinguish it from other medicinal herbs.

Bitter melon is an annual climbing vine reaching about 6.5 feet, characterized by deeply lobed leaves, yellow flowers, and distinctive orange-yellow fruit. Native to southern Asia and now common throughout tropical regions worldwide, it is harvested year-round. Its edible fruit is used both as food and in medicine to treat diabetes in regions including Asia, East Africa and the Caribbean; MSK says data on whether it lowers blood sugar are limited.

Boswellia is a deciduous tree growing to about 49 ft (15 m), characterized by its pale, papery bark, compound leaves, and small clusters of white flowers. The resin of the tree has traditionally been used in Ayurveda for arthritis, inflammation and pain, and some respiratory conditions (NCCIH). The key active components are boswellic acids. NCCIH says some studies suggest oral boswellia may ease osteoarthritis pain and inflammation, but there is not enough high-quality evidence to know whether it helps any health condition.