Can you eat it?
The plant has traditionally been eaten, which shows it is safe for human consumption in reasonable quantities.
To begin with, not all parts of the plant are edible (as with rhubarb) and they are only edible at a certain time of the year. The shoots in the spring are tender enough to eat, but they have to be gathered before the stems become hard and woody. The ideal time to eat knotweed is mid-April to May. However, if you are harvesting it you must ensure that you cause no spread of the plant, as this is illegal within the UK. We recommend that no root material is taken, just the tops of the shoots.
However, the resveratrol contained in it is damaged by heat, so the best way of getting the resveratrol is either by eating a small part of the shoots or making a tincture.
Resveratrol is not readily water soluble. However, this plant tastes a bit like rhubarb, which is not the most pleasant! Also, the emodin within the plant has effects on gastrointestinal ailments, due to laxative effects, so accurate dosing is needed to ensure that these effects are not problematic.
Japanese Knotweed Root may interact with several medications, such as blood thinners and drugs metabolized by the P-450 enzyme system in the liver. Consult your healthcare provider before adding to your regiment of drug treatment.