Yam is a kind of rhizome vegetable that we often eat, also known as dioscorea, potato, etc. Chinese yam is both food and medicine. It is not only a good vegetable to eat, but also a tonic medicine. There has always been a folk saying that "white Chinese yam is better than ginseng". In some parts of China, yam is also called "the food of immortals".

Knotweed, also known as bitter stick, spotted stick and other names, is the dry rhizome and root of Polygonaceae perennial herb Polygonum cuspidatum, which is excavated in spring and autumn. It is not only an ornamental plant, but its tender stems can also be eaten as vegetables. Its roots can be used as cold drinks, and its rhizomes can often be used to make Chinese herbal medicine noodles.