Houttuynia
Houttuynia
Houttuynia cordata
“The herb called juyaku”
| Species | Houttuynia cordata |
|---|---|
| Family | Saururaceae |
| Part used | Terrestrial part, collected in flower |
| Aroma | A strong, distinctive smell from decanoyl acetaldehyde, which fades on drying |
What is dokudami?
Dokudami (Houttuynia cordata) is a perennial distributed from East Asia through Southeast Asia, and native in Japan to Honshu, Shikoku, Kyushu, Okinawa and the Ogasawara Islands (the Hokkaido population was introduced from Honshu). The four white “petals” are bracts. The Japanese Pharmacopoeia lists it as the crude drug juyaku (Houttuyniae Herba), defined as the terrestrial part collected during the flowering season. The Tokyo Crude Drugs Association explicitly frames juyaku as a folk medicine, recording that fresh leaves were traditionally applied to the affected area. It is listed in the Pharmacopoeia yet appears in none of the Pharmacopoeia's kampo extract monographs — an unusual position for a plant: on the books, but used as a folk remedy.
Where the smell comes from
The strong smell of the fresh leaf comes from decanoyl acetaldehyde, which volatilises as the plant dries. In English it is called "fish mint" for the fish-like note. As for the crude-drug name juyaku (“ten medicines”), the dictionaries themselves favour a reading of the Chinese name shuyaku, though a second account — traced to Kaibara Ekiken's Yamato Honzo of 1709 — holds that it was named for ten kinds of medicinal use.
A component of the herb blends used in yakuso steam, simmered with the other plants and turned into steam.
The dried plant is brewed as dokudami tea, and there is a custom of putting the fresh or dried plant in the bath, said to have been used for heat rash and rough skin.
Note: this page introduces the traditions and culture around the plant. It does not guarantee any effect.