Herbal tea

Herbal teas, technically known as herbal infusions, and less commonly called tisanes (UK and US /tɪˈzæn/, US also /tɪˈzɑːn/), are beverages made from the infusion or decoction of herbs, spices, or other plant material in hot water. 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 and in folk medicine.
These "teas" do not usually contain any true tea (Camellia sinensis), but some herbal blends do 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, i.e., processed to remove caffeine).
A number of plants, however, do contain psychoactive compounds, such as 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.
Some feel 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. In any case, the term herbal tea is very well established and much more common than tisane.
Furthermore, in the Etymology of tea, the most ancient term for tea was 荼 (pronounced tu) which originally referred to various plants such as sow thistle, chicory, or smartweed, and was later used to exclusively refer to Camellia sinensis (true "tea").
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.
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.
Herbal teas can be made with any part of a plant, including fresh or dried flowers, fruit, leaves, stems, seeds or roots. These parts may be steeped fully raw (as picked) or processed in some way (such as drying, roasting, crushing, tearing / cutting, steaming, etc.).
Herbal infusions may be made by pouring hot or boiling water over the plant parts and letting them steep for a period of time. The infusion temperature and time can vary depending on the type of plant part used and their properties. For example, some plant parts are covered in oils which may take some time to separate. Brewing with cold water will take much longer as well, usually several hours.
An herbal tea may be strained or not (as with mate where a special straw called a bombilla is used for drinking).
Some herbal teas are blends which include various different herbs or plant parts. Herbal infusions may also be sweetened, spiced, salted, or combined with other additives, like milk or lemon juice.
Some herbal teas are also infused in alcohol, either for medicinal purposes or to make an herbal liquor.
Herbal teas are commonly used in Herbal medicine and in traditional medical cultures, like Indian Ayurveda and Traditional Chinese medicine. Many ancient and medieval Herbal texts contain evidence for the use of various herb infusions throughout human history. Various herbal teas have been promoted throughout history as folk remedies for various diseases and in some cultures they retain their status as local folk cures.
Many companies produce herbal tea bags for such infusions or sell bottled herbal teas.
Herbal teas can be made from any edible plant material, below is a list of common herbal infusions. Some herbal teas are made from plants which contain caffeine, and other herbal infusions may contain other psychoactive compounds. However, many other common herbal teas have not been shown psychoactive properties when compared to placebos, though they may still have some physical effects.
Many herbal teas on the market may also be blends which include various herbs or plant parts. These blends may also include additives, like flavorings.
While most herbal teas are safe for regular consumption, some herbs have toxic or allergenic effects. Among the greatest causes of concern are:
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.
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.
Depending on the source of the herbal ingredients, herbal teas, like any crop, may be contaminated with pesticides or heavy metals. 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".