Polygala tenuifolia

Polygala tenuifolia (yuǎn zhì; ) is an herb in the family Polygalaceae which is hardy to USDA Zone 6.

Phytochemistry
P. tenuifolia contains tenuifolin, senegenin, and polygalacic acid.

Medicinal uses
Yuan zhi is used primarily as an expectorant. It is one of the 50 fundamental herbs used in traditional Chinese medicine, where it is called yuǎn zhì and believed to have neuropsychiatric effects. It has been studied as a potential drug source in depression and Alzheimer's. However, quality of the herb varies widely, and as of 2020 there have been no toxicological studies or clinical trials.