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Arno Kroner, DAOM, LAc, is a board-certified acupuncturist, as well as an herbalist and integrative medicine doctor. He operates a private practice in Santa Monica, California.

Xiao Yao San is a blend of herbs used for centuries in traditional Chinese medicine (TCM). Xiao Yao San is said to clear "liver stagnation" by improving the flow of qi (energy). Stagnant liver qi is said to contribute to stress, mood swings, pain, irritability, constipation, abdominal upset, premenstrual syndrome (PMS), and irregular periods.

The dried ingredients of Xiao Yao San can be hand-blended or purchased as a dietary supplement. The herbs and plants most often used in Xiao Yao San are:

A variation called Jia Wei Xiao Yao San contains all eight herbs with the addition of peony bark and gardenia fruit.

This article explores how Xiao Yao San is used in traditional Chinese medicine, including the scientific evidence to support its use. It also explains how to use Xiao Yao San safely as well as the possible risks and side effects of this ancient Chinese remedy.

Although there are few studies strongly supporting the use of Xiao Yao San (most of which are animal- or lab-based), there are a handful of conditions for which the herbal remedy has shown promise.

An animal study published in Phytotherapy Research suggests that Xiao Yao San may help relieve depression by reducing neuroinflammation (inflammation of the brain and spinal cord).

It is a controversial theory in which imbalances in the gut microflora, bacteria and other microorganisms in the digestive tract, are thought to contribute to neuroinflammation and, in turn, depression. Xiao Yao San is said to help by creating compounds that help normalize the imbalance.

A review of studies published in Evidence-Based Complementary and Alternative Medicine evaluated 26 high-quality trials involving 1,837 people with depression. The researchers concluded that Xiao Yao San appeared to improve depression when taken with an antidepressant. It had no direct effect on depression on its own, however.

In 2009, researchers discovered Xiao Yao San reduced anxiety behaviors in stress-induced rats.  

A later study, also involving rats, linked the effect to a natural hormone called allopregnanolone that is thought to play role in post-traumatic stress syndrome (PTSD). It was found that a daily dose of Xiao Yao San not only lowered anxiety behaviors but also increased levels of allopregnanolone in the brain.  

Anti-inflammatory compounds found in Xiao Yao San, called paeoniflorin and isoliquiritin , may also lessen PTSD symptoms, according to a 2017 review in Frontiers of Pharmacology. Researchers found that both compounds appeared to alter pathways in the brain associated with PTSD.

A lab-based study published in Scientific Reports suggests that Xiao Yao San counteracts oxidative stress in the brain in a similar way as the antidepressant drug Prozac (fluoxetine) commonly used to treat PTSD. Oxidative stress is damage caused to cells by unstable atoms known as free radicals. In the brain, this can lead to neuroinflammation and an increased risk of depression.  

Xiao Yao San is traditionally used to soothe a "sour stomach," also referred to as functional dyspepsia or chronic indigestion.

According to a review of studies published in the Journal of Gastroenterology and Hepatology, Xiao Yao San is able to relieve indigestion symptoms (stomach upset, nausea, bloating, belching) better than acid reflux medications like Motilium (domperidone) and Reglan (metoclopramide).

A 2018 review in Therapeutic Advances in Gastroenterology confirmed the results and suggested Xiao Yao San was more effective in relieving indigestion than either of these drugs.

Despite the positive findings, there was a lack of high-quality studies in these reviews.

There is some evidence that Xiao Yao San may be useful in treating depression, indigestion, and post-traumatic stress disorder (PTSD). Even so, the evidence remains sparse with a lack of high-quality studies on humans to support its use.

Xiao Yao San is generally regarded as safe. Some reported side effects from individual herbs in the blend include:  

Certain components of Xiao Yao San may not be safe for use in some people. If you have any of the following conditions, talk to your healthcare provider before using Xiao Yao San:  

In addition, licorice root is not recommended for people over 65. Long-term use of the herb can cause high blood pressure and lower potassium levels, leading to heart and muscle problems.

Always check with your healthcare practitioner before starting any herb. Mention all drugs and supplements you take, as well as any conditions you have.

Xiao Yao San can cause side effects, including headaches, cramps, dizziness, and upset stomach. People who are pregnant, who are over 65, or who have diabetes, heart disease, or kidney disease should not use Xiao Yao San without first speaking with their doctor.

Xiao Yao San is available as capsules, tinctures, and teapills (herbal extracts compressed into pea-sized balls). It can be found online, at many natural food stores, and in specialty herbalist shops.

Xiao Yao San supplements are sold under different brand names, including Free and Easy Wanderer, Relaxed Wanderer, or Rambling Powder. Xiao Yao Wan is the teapill formulation.

Capsules and teapills are the most convenient forms of Xiao Yao San, but TCM practitioners tend to prefer traditional hand-blended herbs for making decoctions. Decoctions are made by steeping and mashing the mixed ingredients in boiling water to create a therapeutic tonic.

There is no recommended dose of Xiao Yao San in any form. Follow instructions on product labels or provided by your healthcare provider.

Xiao Yao San is sold in capsule, tincture, or "teapill" form as well as traditional hand-blended herbs for use in making decoctions. There is no recommended dose.

Dietary supplements are largely unregulated in the United States. Those imported from China pose extra risks as the ingredients are often written in Chinese and have been known to contain heavy metals, drugs, and other contaminants, according to the National Center for Complementary and Integrative Health.

When choosing a supplement, look for products that have been certified by third-party authorities like ConsumerLab, U.S. Pharmacopeia (USP), or NSF International. These certifying bodies ensure that supplements are pure and only contain the ingredients listed on the product label.

Imported Chinese herbs are not strictly regulated in the United States and pose a risk of contamination. To be safe, opt for supplements that have been certified by the U.S. Pharmacopeia, NSF International, or ConsumerLab.

Xiao Yao San is a mixture of herbs and dried plants—including licorice, dong quai, and poria mushrooms—used in traditional Chinese medicine. It is used to treat a wide range of health conditions, including depression, anxiety, indigestion, constipation, pain, and menstrual problems.

Despite centuries of use, the evidence supporting Xiao Yao San remains relatively weak.

Side effects include nausea, cramps, dizziness, headache, and stomach upset. Certain people should not use it, so consult with your healthcare provider before trying Xiao Yao San.

Although primary care physicians are increasingly familiar with herbal medicines, it may be beneficial to consult a licensed TCM practitioner.

It's unclear. A study published in the journal BMC Complementary and Alternative Medicine found Jia Wei Xiao Yao San is the most prescribed herbal formula for PMS in Taiwan. However, the study authors note there is a lack of published research on its safety or effectiveness in treating PMS.

Teapills are swallowed whole, but because they are so small, a standard dose usually is as many as eight pills taken three times a day. Follow the manufacturer's instructions when taking teapills or other herbal supplements.

There are various translations. The most common is "happy and carefree powder." Others include Leisure Powder, Free Wanderer Powder, Rambling Powder, and Merry Life Powder. Note "san" means powder and "wan" means pill, so the pill form of the herbal formulation typically is called Xiao Yao Wan.

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Zhang Y, Han M, Liu Z, Wang J, He Q, Liu J. Chinese herbal formula xiao yao san for treatment of depression: a systematic review of randomized controlled trials. Evid Based Complement Alternat Med. 2012;2012:931636. doi:10.1155/2012/931636

Gao XX, Cui J, Zheng XY, et al. An investigation of the antidepressant action of xiaoyaosan in rats using ultra performance liquid chromatography-mass spectrometry combined with metabonomics. Phytother Res. 2013;27(7):1074–85. doi:10.1002/ptr.4805

Wang HN, Peng Y, Tan QR, et al. Free and Easy Wanderer Plus (FEWP), a polyherbal preparation, ameliorates PTSD-like behavior and cognitive impairments in stressed rats. Prog Neuropsychopharmacol Biol Psychiatry. 2009;33(8):1458-1463. doi:10.1016/j.pnpbp.2009.07.031

Qiu ZK, Zhang GH, He JL, et al. Free and Easy Wanderer Plus (FEWP) improves behavioral deficits in an animal model of post-traumatic stress disorder by stimulating allopregnanolone biosynthesis. Neurosci Lett. 2015;602:162-166. doi:10.1016/j.neulet.2015.06.055

Hong C, Schüffler A, Kauhl U, et al. Identification of NF-κB as determinant of posttraumatic stress disorder and its inhibition by the Chinese herbal remedy Free and Easy Wanderer. Front Pharmacol. 2017;8:181. doi:10.3389/fphar.2017.00181

Hong C, Cao J, Wu CF, et al. The Chinese herbal formula Free and Easy Wanderer ameliorates oxidative stress through KEAP1-NRF2/HO-1 pathway. Sci Rep. 2017;7(1):11551. doi:10.1038/s41598-017-10443-6

Qin F, Huang X, Ren P. Chinese herbal medicine modified xiaoyao san for functional dyspepsia: meta-analysis of randomized controlled trials. J Gastroenterol Hepatol. 2009;24(8):1320-1325. doi:10.1111/j.1440-1746.2009.05934.x

Chu MHK, Wu IXY, Ho RST, et al. Chinese herbal medicine for functional dyspepsia: systematic review of systematic reviews. Therap Adv Gastroenterol. 2018;11:1756284818785573. doi:10.1177/1756284818785573

Chinese Healing Herbs. Herbs from A to Z.

NIH: National Center for Complementary and Alternative Medicine. Licorice root.

National Center for Complementary and Integrative Health. Traditional Chinese medicine.

Chen HY, Huang BS, Lin YH, et al. Identifying Chinese herbal medicine for premenstrual syndrome: implications from a nationwide database. BMC Complement Altern Med. 2014;14:206. doi:10.1186/1472-6882-14-206

Epsilon Acupuncture. Teapills vs. Tablets—What to Consider.

Liu L, Ge F, Yang H, et al. Xiao-yao-san formula improves cognitive ability by protecting the hippocampal neurons in ovariectomized rats. Evid Based Complement Alternat Med. 2020;2020:4156145. . doi:10.1155/2020/4156145

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