The invention discloses a decoction 
medicine for treating recurrent aphtha and a preparation method thereof. The 
medicine comprises the following components in parts by 
mass: 1-3 parts of cortex moutan, 1-3 parts of radix paeoniae alba, 1-3 parts of dried radix rehmanniae, 1-3 parts of rhizoma cyperi, 1-3 parts of 
radix ophiopogonis, 1-3 parts of cape jasmine, 1-3 parts of 
angelica sinensis, 1-3 parts of rhizoma atractylodis macrocephalae, 1-3 parts of 
radix bupleuri, 1-3 parts of poria cocos, and 1-3 parts of liquorice. The preparation method of the 
medicine comprises the following steps: selecting high-quality, clean and first-grade cortex moutan, radix paeoniae alba, dried radix rehmanniae, rhizoma cyperi, 
radix ophiopogonis, cape jasmine, 
angelica sinensis, rhizoma atractylodis macrocephalae, 
radix bupleuri, poria cocos and liquorice in parts by 
mass, respectively smashing the components into particles for standby application; placing the smashed particular medicine into a cloth bag, tying the cloth bag, soaking the cloth bag into cooled boiled water for about half an hour until the tissue of the medicine is soaked, further, placing the soaked medicine and clear liquor for soaking the medicine into a medicine-decocting 
machine, injecting cooled boiled water, of which the 
water level is 33 mm higher than the medicine, into the medicine-decocting 
machine for carrying out first-time decoction for 35 minutes, filtering away a medicine liquor, injecting slightly warm bolded water to carry out the second-time decoction for 30 minutes, mixing and concentrating into 1665 mL of 50% 
traditional Chinese medicine liquor, bagging, sealing, and then placing the product into a refrigerator for preservation for standby application.