The invention belongs to the field of traditional Chinese medicines, relating to a process for
processing prepared
rehmannia root which is Chinese herbal pieces for decoction. The process comprises the following steps of: soaking
rehmannia root for 12 to 36 hours, and then taking out and draining; adding water 5 to 8 times more than the
rehmannia root, and stewing for 6 to 24 hours; adding 0.5 to 4kg of
amomum fruit and 1 to 6kg of
tangerine peel into every 100kg of the stewed
rehmannia root, continuing to stew for 6 hours, airing till the surfaces of the
rehmannia root is slightly dry, and mixing with the remaining decoction; after the decoction is completely absorbed,
drying at a temperature within a range of 60-80 DEG C till the
moisture content is 12% to 20%, adding 10 to 30g of yellow rice
wine into every 100kg of a dried product, moistening until the yellow rice
wine is completely absorbed,
steaming for 4 to 12 hours, pouring out, and airing to the
room temperature;
cutting the obtained
rehmannia root into slices of 2 to 4mm in thickness, and
drying at a temperature within the range of 60 to 80 DEG C till the
moisture content is 8% to 15%, thereby obtaining the prepared rehmannia root. The prepared rehmannia root produced in the invention has the characteristics of black and bright surface, moist, soft and flexible texture, brilliantly black section, less smell and
sweet taste, and is high in the contents of reducing sugars, polysaccharides and trace elements. The yield of the prepared rehmannia root is 60%-70%.