What is the function that six flavour rehmannia pill and return spleen pill eat together

Liuwei Dihuang Pill and Guipi Pill are used together, mainly for heart and spleen deficiency plus kidney yin deficiency. The combination of the two can nourish kidney yin, spleen, blood and calm the nerves. Liuwei Dihuang Pill is a medicine for nourishing kidney yin. It consists of six kinds of medicines, such as rehmannia root, Huaishan, cornus fruit, cortex moutan, alisma orientalis, Poria cocos, three tonification and three purgation, which can treat dizziness, tinnitus, waist and knees yin deficiency caused by kidney yin deficiency and night sweat. Guipi Pill is mainly used to treat deficiency of both heart and spleen, deficiency of qi and blood, and some corresponding manifestations caused by deficiency of qi and blood.