Rehmannia (Rehmannia glutinosa) is a widely used traditional Chinese herb. It is used to nourish Yin and invigorate the kidney in traditional Chinese medicine (TCM) and has a very high medicinal value. Studies show that Rehmannia glutinosa and its active principles possess wide pharmacological actions on the blood system, immune system, endocrine system, cardiovascular system, and the nervous system. I regularly use Rehmannia for stress and anxiety conditions and regularly combine with Ashwagandha, Chamomile, Passionflower, Rhodiola, Schisandra, Ziziphus, Magnesium, and the B Vitamins. It combines well with classic adaptogen herbs.
Reference: Zhang R-X et al. Rehmannia glutinosa: review of botany, chemistry and pharmacology. J Ethnopharmacol. 2008 May 8; 117(2): 199-214.