Beverage made from infusing or decocting plant material in hot water
Herbal teas, also known as herbal infusions and less commonly[2] called tisanes (UK and US /tɪˈzæn/, US also /tɪˈzɑːn/),[3] are beverages made from the
infusion or
decoction of
herbs,
spices, or other
plant material in hot water; they do not usually contain any true tea (Camellia sinensis). Often herb tea, or the plain term tea, is used as a reference to all sorts of herbal teas. Many herbs used in teas/tisanes are also used in
herbal medicine. Some herbal blends contain true
tea (e.g., the Indian classic
masala chai).
The term "herbal" tea is often used to distinguish these beverages from true
teas (e.g.,
black,
green,
white,
yellow,
oolong), which are prepared from the cured leaves of the tea plant, Camellia sinensis. Unlike true teas, most tisanes do not naturally contain
caffeine (though tea can be
decaffeinated, processed to remove caffeine).[4][5] A number of plants, however, do contain caffeine or another
stimulant, like
theobromine,
cocaine or
ephedrine. Some have the opposite effect, acting as a
sedative. Some common
infusions have specific names such as
mate (yerba mate) and rooibos (red bush).
Hibiscus tea is one type of herbal infusion, but many described as some other plant have hibiscus as the main ingredient, or a major one.[6]
Etymology
Some feel[clarification needed] that the term tisane is more correct than herbal tea or that the latter is even misleading, but most dictionaries record that the word tea is also used to refer to other plants beside the
tea plant and to beverages made from these other plants.[7][8] In any case, the term herbal tea is very well established and much more common than tisane.[2]
The word tisane was rare in its modern sense before the 20th century, when it was borrowed in the modern sense from French. (This is why some people feel it should be pronounced /tɪˈzɑːn/ as in French, but the original English pronunciation /tɪˈzæn/ continues to be more common in US English and especially in UK English.)[3]
The word had already existed in late
Middle English in the sense of "medicinal drink" and had already been borrowed from French (
Old French). The Old French word came from the Latin word ptisana, which came from the
Ancient Greek word πτισάνη (ptisánē), which meant "peeled" barley, in other words
pearl barley, and a drink made from this that is similar to modern
barley water.[9]
Herbal teas can be made with fresh or dried flowers, fruit, leaves, seeds or roots. They are made by pouring boiling water over the plant parts and letting them steep for a few minutes. The herbal tea is then strained, sweetened if desired, and served. Many companies produce herbal
tea bags for such infusions.
Coca tea, infusion made from
coca leaves. Contains trace amounts of
cocaine and similar alkaloids.[10] 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 from the leaf using the same chemicals as manufacturing cocaine.
Hydrangea tea, dried leaves of hydrangeas; considerable care must be taken because most species contain a toxin. The "safe" hydrangeas belong to the Hydrangea serrata Amacha ("sweet tea") cultivar group.[11]
Jiaogulan (also known as xiancao or "poor man's ginseng")
Kava root, from the South Pacific, can be made into a tea for stomach upsets and other minor illnesses. The traditional form is a water-based suspension of kava roots.
Mountain tea, common 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 3,000 feet. Records of its use date back 2,000 years.
Roasted
wheat, used in
Postum, a coffee substitute
Rooibos (red bush), 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 characteristics of
green tea, but because it does not come from tea leaves, it has no
caffeine.
While most herbal teas are safe for regular consumption, some herbs have
toxic or
allergenic effects. Among the greatest causes of concern are:
Comfrey, which contains
alkaloids which may be harmful to the
liver from chronic use, and particularly is not recommended during pregnancy or when
prescription drugs are used; comfrey is not recommended for oral use.[13]
Lobelia, which contains alkaloids and has
traditional medicine uses for smoking cessation, may cause nausea, vomiting, or dizziness at high doses.[14]
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 toxic to the liver) comfrey. Care must be taken not to use any
poisonous plants.
The US does not require herbal teas to have any evidence concerning their efficacy, but does treat them technically as food products and require that they be safe for consumption.
Fruit or fruit-flavored tea is usually acidic and thus may contribute to erosion of
tooth enamel.[15]
Some phytochemicals found in herbs and fruits can adversely interact with others and over the counter or prescription medications, among other ways by affecting their metabolism by the body. Herbs and fruits that inhibit or induce the body's Cytochrome P450 enzyme complex function can either cause the drug to be dangerously ineffective, or increase its effective absorbed dose to potentially toxic levels, respectively. Best known examples of adverse herb‑drug interactions are
grapefruit or
St John's wort, contraindicated for several medications including
Paxlovid and
oral contraceptives, but other herbs also affect the CYP enzyme family, showing herb‑drug interactions.[16][17][18]
Depending on the source of the herbal ingredients, herbal teas, like any crop, may be contaminated with
pesticides or
heavy metals.[19][20]
According to Naithani & Kakkar (2004), "all herbal preparations should be checked for toxic chemical residues to allay consumer fears of exposure to known neuro-toxicant pesticides and to aid in promoting global acceptance of these products".[19]
^"Blackberry & Blueberry infusion". Sainsbury's. Retrieved 6 March 2024. A typical example, described as Blackberry & Blueberry, but has hibiscus as main ingredient, and 0.5% of the named ingredients.
^
abNaithani, V; Kakkar, P (2004). "An evaluation of residual organochlorine pesticides in popular Indian herbal teas". Archives of Environmental Health. 59 (8): 426–30.
doi:
10.3200/AEOH.59.8.426-430.
PMID16268119.
S2CID31026817.
^Naithani, V; Kakkar, P (2005). "Evaluation of heavy metals in Indian herbal teas". Bulletin of Environmental Contamination and Toxicology. 75 (1): 197–203.
doi:
10.1007/s00128-005-0738-4.
PMID16228893.
S2CID41011619.