Sān miào wán is a traditional Chinese medicine

Traditional Chinese medicine

Traditional Chinese Medicine refers to a broad range of medicine practices sharing common theoretical concepts which have been developed in China and are based on a tradition of more than 2,000 years, including various forms of herbal medicine, acupuncture, massage , exercise , and dietary therapy...

 consisting of three components:

• 33% huáng bǎi
  Huáng bǎi
  Huáng bǎi or huáng bò is one of the fifty fundamental herbs of traditional Chinese medicine. Known also as Cortex Phellodendri, it is the bark of one of two species of Phellodendron tree: Phellodendron amurense or Phellodendron chinense.]- Cultivation :For Phellodendron amurense Huáng bǎi (黄栢 or...
  
   (黃栢 or "yellow fir"), also known as Cortex Phellodendri, the bark of Phellodendron chinense
  Phellodendron chinense
  Phellodendron chinense is a plant species in the genus Phellodendron.The isocoumarin derivative 3-acetyl-3,4-dihydro-5,6-dimethoxy-1H-2-benzopyran-1-one can be found in Huáng bǎi , one of the fifty fundamental herbs of traditional Chinese medicine....
  
  Schneid. or Phellodendron amurense
  Phellodendron amurense
  Phellodendron amurense Rupr. is a species of tree in the family Rutaceae, commonly called the Amur cork tree. It is a major source of huáng bò , one of the 50 fundamental herbs used in traditional Chinese medicine...
  
  Rupr.

• 50% cāng zhú
  Cāng zhú
  Cāng zhú , also known as black atractylodes rhizome or Rhizoma Atractylodes, is a Chinese herbal medicine. It is the dried rhizome of Atractylodes lancea DC., Atractylodes chinensis Koidz, or certain other local species including Atractylodes japonica Koidz. Cāng zhú (苍术 or 蒼术 or 蒼朮), also...
  
   (蒼术 or "[black] atractylodes"), also known as Atractylodis Rhizoma, the root of Atractylodes lancea
  Atractylodes lancea
  Atractylodes lancea Thunb. is a species of Atractylodes that grows in central China . It is one source of cāng zhú, a Chinese herbal medicine that acts primarily on the digestive system....
  
  (thunb.) Dc or Atractylodes chinensis (dc.) Koidz.

• 17% huái niú xī (懷牛膝 or "ox knee"), also known as Archyanthis bidentatae Radix, the root of Achyranthes bidentata
  Achyranthes bidentata
  Achyranthes bidentata Blume is a species of Achyranthes that grows in India, Nepal, China, and Japan. It is the source of Huái niú xī, a Chinese herbal medicine with anti-inflammatory activities. In Nepal its root juice is used for toothache. Its seeds have been used as a substitute for cereal...
  
  .

The preparation, as well as related herbal combinations such as èr miào wán (二妙丸, "two marvel pill", which contains equal proportions of huáng bǎi and cāng zhú) and sì miào wán (四妙丸, "four marvel pill"), has been used traditionally in treatment of gout

Gout

Gout is a medical condition usually characterized by recurrent attacks of acute inflammatory arthritis—a red, tender, hot, swollen joint. The metatarsal-phalangeal joint at the base of the big toe is the most commonly affected . However, it may also present as tophi, kidney stones, or urate...

. Sān miào wán has been reported to lower serum and liver uric acid concentration in mice with hyperuricemia

Hyperuricemia

Hyperuricemia is a level of uric acid in the blood that is abnormally high. In humans, the upper end of the normal range is 360 µmol/L for women and 400 µmol/L for men.-Causes:...

, but not normal mice, by suppressing xanthine oxidase

Xanthine oxidase

Xanthine oxidase Xanthine oxidase Xanthine oxidase (XO (sometimes 'XAO'), a form of xanthine oxidoreductase that generates reactive oxygen species. Is an enzyme that catalyzes the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid...

 and downregulating production of mRNA for renal uric acid transporter mURAT1.