Tonify the yang (bu yang)

Herbs that tonify the yang are warming herbs that fortify the yang aspect of the Kidneys which is the source of yang for the entire body, notably the Spleen and Heart. Yang deficiency presents primarily with exhaustion and lack of warmth, but also withdrawal into oneself, cold limbs, fear of cold, weak and sore lower back and legs, possibly accompanied by impotence, palpitations, sweating, urgency or leakage from the lower orifices and wheezing.

Examples include dong cong xia cao (cordyceps, Cordyceps sinensis), du zhong (Eucommia bark, Eucommia ulmoides), xu duan (teasel root, Dipsacus asperoides) and bu gu zhi (babchi seeds, Psoralea corylifolia), tu si zi (dodder seed, Cuscuta chinnsis) and hu la ba (fenugreek, Trigonella foenum-gracum).