Xiao Yao Wan is an ancient Chinese patent medicine with a history of more than 1,000 years.
In the early days, the output of Chinese herbs was not high.
[2][5] Xiao Yao San (XYS) has been used for centuries by practitioners of Chinese Traditional Medicine.
Practitioners of TCM believe XYS works by clearing liver stagnation to improve the flow of qi (energy).
Stagnant liver qi is said to affect the blood and contribute to stress, mood swings, pain, irritability, constipation, abdominal pain, premenstrual syndrome (PMS), and irregular menstrual periods.