Radix Rehmanniae Praeparata is used for tonifying blood and nourishing yin, benefiting the essence and filling in the marrow. It is used for treating blood deficiency, palpitation (rapid heartbeat, often accompanied by panic), dysmenorrhea, metrorrhagia (excessive menstrual flow or dribbling of menstruation), and hemorrhagic discharges. Radix Rehmanniae Praeparata (熟地黄) is slightly warm in nature, sweet in flavor, and belongs to the liver and kidney meridians. It is used in treating blood deficiency with yellowish color, palpitation and dizziness, irregular menstruation, discharging of blood after menstrual bleeding, yin deficiency of liver and kidney (deficiency of yin in liver and kidney), lumbar and knee soreness (feeling of soreness and weakness in lumbar and knee), bone vapor and tidal fever (a burst of heat, feeling that the heat is penetrating from inside the bone to the outside), and night sweating (sweating abnormally after falling asleep, but stopping after waking up). It should be noted that it is contraindicated for people with weak spleen and stomach, stagnant qi and phlegm, and fullness of the abdomen and loose stools (thin and unformed feces). Although there is no clear adverse reaction to Radix Rehmanniae Praeparata, it is recommended to take the medicine under the guidance of a Chinese medicine practitioner, rather than taking the medicine on your own, in order to avoid delays or adverse reactions.