10/10/2025
Episode 26 - Japanese knotweed (Reynoutria japonica) is often labeled an invasive menace, but beneath that reputation lies a plant with remarkable medicinal and cultural depth.
In addition to the compounds mentioned in the video, its roots contain phenolic acids, flavan-3-ols, flavones such as luteolin and kaempferol derivatives, phenylpropanoid and lignan compounds, coumarins, and naphthoquinones, including torachrysone, which is part of what makes this plant so chemically rich and multifaceted.
In Japan, it’s known as itadori, meaning “pain remover.” Beyond its medicinal uses, itadori has long been part of daily life, eaten as a spring vegetable, used in folk remedies, floral arrangements, and even children’s play. Its young shoots are tender and edible when harvested early, often compared to rhubarb or asparagus and used for pies, pickles, and syrups.
Stay tuned for Part 2, where we’ll explore how these diverse compounds actually work in the body, and why herbalists consider Japanese knotweed such a powerful ally.