Polygonum cuspidatum, known by the common name Japanese knotweed, is a tall, stout herbaceous perennial (Seiger, 2005) and is a member of the Polygonaceae (Seiger, 2005).In China it is referred to as Hu Zhanz. Japanese knotweed is also known under the scientific names Fallopia japonica and Reynoutria japonica.olygonum cuspidatum has many different positive medicinal uses, mainly from the stilbene compound, resveratrol, and its derivatives. Severe side effects directly from the derivatives of the plant, which are unknown, make it a useful herbal remedy.