solstice liu wei di huang wan herbal supplement (200 pills) solstice medicine company contains chinese yam rhizome which is an ornamental vine that grows extensively in asia. it also can grow in north america, but it is unrelated to sweet potatoes in the us. chinese yam also is known as cinnamon vine. the roots of this yam contain disgenin. chinese yam can be useful in supporting the health of the male reproductive system and provide support for the joints. it supports the function of kidneys, as well.