History

• Japanese knotweed was brought to the West from East Asia in the late 19th century as an ornamental garden shrub. But it soon spread beyond its boundaries to infest areas from coast to coast. It has now colonized all manner of roadsides, vacant lots, railway lines and gardens, to the dismay of gardeners. Although in the East it has long been used as a medicinal substance and as a food, it has only recently been considered for these purposes in the West. Although it is easy to find in North America, the medicinal herb is mainly imported from China.
  
  

Research Findings

• Science has isolated chemicals in Japanese knotweed that act as antimicrobials, antioxidants and antimutagens in cancer. Other substances have been shown to heal burns and boost the immune system and heart function. Of particular interest is the plant as a source of reservatrol, the same substance found in red wine that has been shown to promote heart health. In addition, the plant contains emodin and chrysophanol. The three compounds have shown potential to fight tumors and their spread.
  
  

Traditional Healing

• In traditional Chinese medicine (TCM), the herb is considered to have bitter and "cold" properties. It works to stimulate blood circulation, clear heat and remove toxins.
  
  In TCM, the dried root and stem of Japanese knotweed (hu zhang) has been used to treat cancer, high cholesterol and constipation. It is also used to treat arthritis, painful joints, menstrual complaints, skin sores and traumatic injuries. It is most often used in a formula with other herbs. Because of its astringent and antimicrobial properties, it has been used in skin preparations and massage creams.
  
  

As a Food

• Japanese Knotweed is a Tangy Vegetable.
  
  The young stems of the plant can be eaten in salads or cooked as a green vegetable. The stalks can also be used in recipes as a substitute for rhubarb. The shoots are best used when they are 6 to 8 inches tall. Peeled and sliced, they can be steamed as a tart vegetable or cooked in soups and sauces. They provide Vitamin A and Vitamin C, as well as essential minerals.
  
  

Warnings

• Japanese knotweed can produce a rash. It has also been reported to contain carcinogenic tannins that counteract digestive enzymes.