The objective of this study was to investigate Rehmannia 14 (R14), a Chinese herbal medicine, reported to be effective in treating endocrine and renal function disorders in geriatric and Kidney Yang Deficiency cases. Using a geriatric and Kidney Yang Deficiency mouse model (GKDM) with a control group, 60 male Kunming mice expressing clinical signs of GKDM (weight loss, lethargy, cool limbs, decreased rectal temperature) were treated with R14 to investigate its impact on serum concentrations of triiodothyronine (T3), tetraiodothyronine (T4), thyroid stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), cortisol (COR), creatinine (CRE), blood urea nitrogen (BUN) and the content of nitric oxide (NO) in renal homogenates. Study results demonstrated that GKDM model mice had decreased body weight/rectal temperatures and lethargy while R14 treated animals had improved weight gains/normal rectal temperature and improved activity levels. The GKDM mice also had decreased T3/T4/ACTH with increased TSH while the R14 dosed animals had increased T3/T4/ACTH and decreased TSH levels. In addition, R14 exerted protective effects on the kidneys with decreased NO, CRE and BUN concentrations. Study findings concluded that R14 improved serum concentrations of key endocrine indicators of disorders of the hypothalamic-pituitary-adrenal axis and has a protective effect on renal function in a GKDM mouse model. The findings from this study provide a basis for the clinical use of R14 in the treatment of endocrine and renal disorders associated with aging and Kidney Yang/Qi Deficiency in animals.