Japanese Knotweed (Polygonum cuspidatum) is widely used in Chinese Medicine, where it is known as Hu Zhang (Tiger Cane). The root is the part used and in my opinion, it is a plant medicine that American herbalists should use more frequently.
Many of you are probably quite familiar with this herb as it is an aggressive, difficult to eradicate, weedy plant. I have actually seen it paved over with macadam and grow right through the asphalt.
The dried root is used in TCM to dispel damp heat and wind damp conditions with blood stasis and pain. From a western perspective this means it acts as an anti-inflammatory, antibacterial and analgesic.
It is used to treat osteo- and rheumatoid arthritis, trauma injuries (orally and topically) and I find it to be quite effective for treating Lyme-induced arthritis and post-Lyme arthralgias.
Having said that, there are many websites that claim this herb can "cure" Lyme disease. I can say with a fair amount of certainty that it does not.
The root is also used for damp heat (inflammation and/or infection) in the genitourinary, gastrointestinal and respiratory tracts and has been successfully used as part of a protocol to treat jaundice, dysentery, hepatitis, nephritis, bronchitis and pneumonia.
Japanese Knotweed is the richest known source of the antioxidant stilbene known as Res
veratrol and the young tops can be cooked and eaten, with a taste similar to Rhubarb.