You Gui Wan (YGW) is a formula that treats Kidney Yang Deficiency, decline of Ming-men (life gate) Fire, and replenishes Kidney Jing and Blood. Characteristic clinical signs of Kidney Yang Deficiency include: low energy, exercise intolerance, cold extremities, impotence/low sperm count, fecal/urinary incontinence, loose stools with undigested food, weakness of the back/stifles and rear leg edema. The tongue will be pale pink to purple, may be wet and swollen with teeth marks accompanied by a deep, weak, thin pulse that is weaker on the right and slow in severe cases. Veterinary conditions that can be treated with this formula include: infertility, laminitis, renal disease, urinary incontinence, endocrine disorders, rear weakness, arthritis and bronchial asthma. Animal model studies have demonstrated YGW can improve immune function, even in cases with severe immunosuppression and additionally has protective effects against glucocorticoid induced immune changes. In chronic allergic asthmatic mice, it was demonstrated that the regulative effects exerted by YGW on affected mice was via its anti-inflammatory activity and inhibition of reactive airway remodeling. Evaluation of the effects of YGW on sperm fertility in mice demonstrated that YGW has a significant effect on normal sperm fertilizing ability both in vivo and in vitro. Geriatric frequent urination was successfully treated by using YGW plus Suo Quan Wan formula in a study.