Encyclopedia of Diets - A Guide to Health and Nutrition

of anxiety, depression, and various sleep disorders. St.

John’s wort is classified in the kingdom Plantae, divi-

sion Magnoliophyta, class Magnoliopsida, and order

Malpighiales. It is usually classified within the family

Hypericaceae but is also sometimes found within the

family Clusiaceae. Its genus isHypericum.

When St. John’s wort is used to refer to the herb

used to treat illnesses such as depression, it is the species

informally called Common St. John’s wort. Sometimes

also called Goat weed, hypericum, and Klamath weed,

it is the most plentiful species of St. John’s wort in the

world. It is classified as genus/speciesHypericum perfo-

ratum. As a perennial herb, St. John’s wort has the

ability to produce complicated underground creeping

stems, called rhizomes. Its above-ground stems are

straight and upright, branched within its upper half,

and able to grow up to one meter (three feet) in height.

BesidesH. perforatum, St. John’s wort can also refer

to the other species of St. John’s wort including scrubby

St. John’s wort (Hypericum prolificum), great St. John’s

wort (Hypericum ascyron), and Jerusalem star, or rose of

Sharon (Hypericum calycimum). In all, about 370 species

of the genusHypericumare found around the world.

Supposedly, the plant genus (Hypericum) was given

its name—from the Greek words hyper (above) and

eikon (picture)—in reference to John the Baptist, the

first centuryA.D. Jewish religious leader. The exact

reason for the naming is in question. Some of the

possible reasons for its name include: the blooming of

its yellow flowers in June around the time of John the

Baptist’s birth; the presence of the flower at a feast of

John the Baptist; and the hanging of the flower over

pictures in houses to supposedly protect against evil on

St. John’s day.

Purpose

St. John’s wort has been used for centuries to med-

ically treat mental disorders such as depression and

anxiety. The ancient Greek civilization is known to

have used it for this purpose. Early Native Americans

used it as anti-inflammatory (to control inflammation),

antiseptic (to control infection), and astringent (to

bring tissues together) medicines. The flowers of the

plant have been used to treat depression, anxiety, and

insomnia; sedate people; as a treatment for malaria;

and a balm for burns, insect bites, and wounds. In

recent history, parts of the plant have been used within

herbal tea.

However, it is also considered a poisonous weed in

over twenty countries. St. John’s wort is considered a

toxic weed that invades more productive plants and

flowers. When eaten by domesticated animals, such as

cows and horses, it can cause problems in the central

nervous system, abortion in pregnant females, and

even death.

Today, the flowers of the St. John’s wort

contains hypericin, a chemical that supposedly has anti-

inflammatory and antidepressant properties. TheHyper-

icumextract, which is obtained fromH. perforatumis

used in the United States as a popular herbal medicine

(alternative to standard medicine) for the treatment of

mild depression. In the United States, according to the

National Institutes of Health (NIH), St. John’s wort is

one of the leading herbal products sold. This sales volume

St. John’s wort flowers.(Photo Researchers, Inc. Reproduced

by permission.)

KEY TERMS

Anticoagulants—Blood thinners.

Antiseptic—Medicine used to control infection.

Astringent—Substance that brings tissues together.

Extract—A compound in which something has

been taken out so that it is now in a more purified

state.

Placebo—An inactive substance (such as a sugar

pill) used as a control in experiments.

Perennial—Reoccurring, as a plant that comes

back for more than one growing season.

Rhizome—An underground creeping stem.

St. John’s wort