There is no such thing as “the best combination of Radix Rehmanniae Pill with Conjugated Zi”. Radix Rehmanniae Pill can be used in combination with Si Shen Pill for the treatment of diarrhea and kidney yang deficiency (deficiency of yang qi in the kidneys). Before using the medication, a professional Chinese medicine practitioner is required to identify the symptoms of the disease, and the medication should correspond to the symptoms in order to treat the disease. Radix Rehmanniae Pill with Radix Rehmanniae Pill combined with Si Shen Wan can be used for treating diarrhea and kidney yang deficiency (deficiency of yang qi in the kidneys), with pain in the umbilical cord and abdomen before dawn, followed by intestinal tinnitus and diarrhea, undigested food in the bowels, restfulness after diarrhea, coldness in the form of chills, cold limbs, and aching of the waist and knees (aching and weakness of the waist and knees). It can also be used with cinnamon and Wu Zhu Zhu to treat spleen yang deficiency (deficiency of yang qi in the spleen), cold pain in the abdomen due to yin-cold internalization, lack of warmth in the hands and feet, and loose stools. The adverse reactions and contraindications of Radix Rehmanniae Pill are not clear, it is contraindicated for people with excessive menstruation, pregnant women, and the drug should not be taken when you have a cold. Drugs need to be taken under the guidance of a doctor, do not blindly self-medication.