An herbal tea, tisane, or ptisan is an herbal infusion made from anything other than the leaves of the tea bush (Camellia sinensis). The English word "tisane" originated from the Greek word πτισάνη (ptisanē), a drink made from pearl barley. Strictly speaking, the name 'herbal teas' is a misnomer, as they are not made with real tea (Camellia sinensis), but by infusing other plants. In many countries (but not in the United States the use of the word tea is legally restricted to infusions of Camellia sinensis (the tea plant).
Herbal teas can be made with fresh or dried flowers, leaves, seeds or roots, generally by pouring boiling water over the plant parts and letting them steep for a few minutes. Seeds and roots can also be boiled on a stove. The tisane is then strained, sweetened if so desired, and served. Many companies produce herbal tea bags for such infusions.
On the other hand, flavoured teas are prepared by adding other plants to an actual tea (black, oolong, green, yellow, or white tea); for example, the popular Earl Grey tea is black tea with bergamot, jasmine tea is Chinese tea with jasmine flowers, and genmaicha is a Japanese green tea with toasted rice.
Varieties of herbal infusions include:
- Anise tea, made from either the seeds or the leaves.
- Artichoke tea, with purported health benefits .
- Roasted barley, known in Japanese as mugicha and Korean as bori cha. The roasted flavor can be reminiscent of coffee (without coffee's bitterness and caffeine). It is often drunk cold in the summer.
- Bissap, consumed in the Sahel.
- Boldo, used in South America to calm upset stomachs.
- Cannabis, used in the preparation of Bhang.
- Che Dang, very bitter tea made from Ilex causue leaves.
- Catnip tea is used as a relaxant, sedative, and to calm.
- Cerasse, a bitter Jamaican herb 
- Chamomile tea is used as a sedative. In Beatrix Potter's The Tale of Peter Rabbit, Peter's mother gives him chamomile tea.
- Chrysanthemum tea, made from dried flowers, is popular with Chinese Dim sum.
- Citrus peel, including bergamot, lemon and orange peel.
- Roasted corn, known in Korea as oksusu cha (옥수수차)
- Dill tea, often consumed to ease upset stomach.
- Echinacea tea, often consumed to prevent or alleviate the cold or flu symptoms.
- Essiac tea, a blended herbal tea.
- Ginger root
- Hibiscus (often blended with rose hip), a popular tea alternative in the Middle East which is drunk hot or cold. Hibiscus tea is also consumed in Okinawa, where the natives associate Hibiscus tea with longevity.(See Bissap)
- Honeybush is related to rooibos and grows in a similar area of South Africa, but tastes slightly sweeter.
- Kapor tea, dried leaves of fireweed.
- Kava root, from the South Pacific, is popular for its effects in promoting talkativeness and relaxation.
- Kuding, a bitter tisane found in Chinese herbal medicine and used to thin blood and reduce blood pressure
- Labrador tea, made from the shrub by the same name, found in the northern part of North America.
- Lapacho (also known as Taheebo) is the inner-lining of the bark (or cambium) of the Red or Purple Lapacho Tree which grows in the Brazilian jungles. It is boiled to make an infusion with many and varied health benefits.
- Lemon grass
- Licorice root
- Lime blossom, dried flowers of lime tree (Tilia in Latin).
- Lotus flower, from the stamens of Nelumbo nucifera (as in Vietnamese trà sen).
- Mate (or yerba mate) is a shrub grown mainly Argentina, Uruguay and Brazil from which a caffeinated, tea-like brew is prepared.
- Mate de coca (sometimes called "coca tea"), made from coca leaves. Authentic mate de coca contains very small amounts of cocaine and similar alkaloids. In some countries where coca is illegal, products marketed as "coca tea" are supposed to be decocainized, i.e., the pharmacologically active components have been removed.
- Mint, especially peppermint (also mixed with green tea to make mint tea)
- European mistletoe (Viscum Album), (steep in cold water for 2-6 hours)
- Mountain Tea, a very popular tea in the Balkans and other areas of the Mediterranean region. Made from a variety of the Sideritis syriaca plant which grows in warm climates above 3000 feet. The tea (or more properly tisane) has a reputation as a cure-all, but is specifically used against colds. Records of its use date back 2000 years.
- Neem leaf
- Nettle leaf
- Pennywort leaf, in Southeast Asia
- Red raspberry leaf
- Scorched rice, known as hyeonmi cha in Korea
- Rooibos (Red Bush) is a reddish plant used to make an infusion and grown in South Africa. In the US it is sometimes called red tea. It has many of the antioxidant benefits of green tea, but because it does not come from tea leaves, it has no caffeine.
- Rose hip (often blended with hibiscus)
- Staghorn Sumac
- Stevia can be used to make herbal tea, or as a sweetener in other tisanes. Be advised: Stevia may be carcinogenic.
- Sugarcane drink, in Asia
- Uncaria tomentosa, commonly known as Cats Claw
- Roasted wheat is used in Postum, a coffee substitute.
- Wong Logat a medicinal tea with several herbs
- Wax gourd in East Asia and Southeast Asia.
- Yerba Mate Popular in South America. Scientific name Ilex paraguariensis.
- Yuen Kut Lam Kam Wo Tea Composed of thirty Chinese herbs, made in Hong Kong.
- Tan Ngan Lo Medicated Tea a herbal concoction formulated by a Chinese immigrant from mainland China in the early 20th century, made in Malaysia.
Herbal teas are often consumed for their physical or medicinal effects, especially for their stimulant, relaxant or sedative properties. The medicinal effects of certain herbs are discussed under herbalism. The medicinal benefits of specific herbs are often anecdotal or controversial, and in the United States and elsewhere, makers of herbal teas are not allowed to make unsubstantiated claims about the medicinal effects of their products.
- Comfrey, which contains alkaloids that can cause permanent liver damage with chronic use.
- Lobelia, which contains toxins similar in effect to nicotine. Although Lobelia is known for its astounding blood cleansing qualities.
- Chamomile and Pineapple weed (another Matricaria species), are closely related to ragweed and can cause violent allergic reactions in hay fever sufferers, up to and including anaphylactic shock and death.
Herbal teas can also have different effects from person to person, and this is further compounded by the problem of potential misidentification. The deadly foxglove, for example, can be mistaken for the much more benign (but still relatively hepatotoxic) comfrey.
The UK currently does not require natural products such as herbs to have any evidence concerning their efficacy, but does treat them technically as food stuff and require that they are safe for consumption.
Herbal tea, along with hot chocolate, was the favorite drink of Agatha Christie's sleuth, Hercule Poirot. In numerous stories, Poirot brews a tisane in order to recover from wet weather or to soothe his 'little grey cells.'
- Rachel Levin, "A Healthy Heart; Artichokes: The Thorny Thistles"