Swertia japonica is a
biennial plant native mainly to
Japan, but also found in
Korea and
China. Its leaves are
linear and it has small flowers with a
corolla diameter of 2 to 3 centimeters. The flowers have five petals and are white with purple veins. The plant can grow from 5 to 50 centimeters in height. It is said that the plant was named because it tastes bitter even after being boiling a thousand times: the
Japanese word meaning 'thousand'. The plant is a
biennial flowering plant with a two-year biological life cycle. During their first year, seedlings produce several
internodes, which elongate after the spring of the second year. The plant can be harvested by the following October, when its flowers open. The plant's seed is tiny and does not
germinate readily, so it can easily be defeated by weeds. The traditional medicinal form of
Swertia japonica is known as in Japan. According to
Comprehensive Natural Products II: Chemistry and Biology, it is considered to be one of the most popular medicinal herbs and one of the bitterest herbs in Japan. It has also been found to be an effective
anticholinergic. According to
Wakan Sansai Zue, a decoction of the herb was used as a laundry additive during the
Edo Period to act as an insecticide for fleas and lice. It was also mixed with glue to treat against insect damage. ==See also==