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Xiao Yao San (Free and Easy Wanderer)

Xiao Yao San (Free and Easy Wanderer): its eight published ingredients, Song dynasty origin, what reviews of trials in depression, anxiety, digestion and sleep found, and safety cautions.

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What it is

Xiao Yao San ("Free and Easy Wanderer," also Xiaoyao San, Soyo-san in Korean and Shoyo-san in Japanese) is a classical Chinese herbal formula. It is made as a powder, decoction or pill, and "modified" versions with extra herbs are common in research. This page is information only. It gives no doses and no instructions for preparing or taking it.

Origin and published composition

A trials review says it was recorded in the Song dynasty text Taiping Huimin Heji Jufang (1078 to 1085 AD) and lists eight components: Radix Bupleuri, Radix Angelicae Sinensis, Radix Paeoniae Alba, Rhizoma Atractylodis Macrocephalae, Poria, Herba Menthae Haplocalycis, Rhizoma Zingiberis Recens and Radix Glycyrrhizae. [1] A second review names the species, including Bupleurum chinense, Paeonia lactiflora, Angelica sinensis, Glycyrrhiza uralensis and Zingiber officinale. [2] Ingredient guides on this site: Bupleurum, Dong Quai, Poria, licorice and ginger.

How it is traditionally explained

Practitioners attach traditional pattern names to the formula, such as liver qi stagnation. These are TCM frameworks, not diagnoses a lab can confirm; see common TCM patterns and pattern differentiation. Modern papers often say the formula "adjusts gastrointestinal function and improves mental and psychological abnormalities," but that is the reviewers' description of its use in China. [1]

What research measured

Most trials are Chinese, and many compare the formula plus a drug against the drug alone; reviews call for long-term, double-blinded trials. [1] Evidence labels apply to that exact use.
6 findings · 2 supported · 4 limited or unclearThe colour follows the evidence label on each card.

  1. Post-stroke depression, added to antidepressants

    Promising but limited

    41 trials (3,628 people): lower Hamilton Depression scores (mean difference -4.01), but certainty was low to very low and heterogeneity high (I2 = 94%). [2]

  2. Depression after breast cancer surgery

    Insufficient evidence

    11 trials (748 people): formula plus antidepressant improved depression scores more than the antidepressant alone; the formula alone did not significantly improve them. [3]

  3. Depressive disorders in general

    Insufficient evidence

    A qualitative synthesis of 21 trials (2,766 people) suggested fewer stomach and sleep side effects than comparison drugs, but adverse-event reporting was incomplete in earlier trials. [4]

  4. Functional gut disorders

    Promising but limited

    48 trials (4,403 people): higher "effective rate" than Western drugs (risk ratio 1.23) and lower anxiety and depression scores; the authors still called trial quality limited. [1]

  5. Insomnia with anxiety

    Insufficient evidence

    9 trials (681 people): better sleep and anxiety scores as an add-on; low methodological quality, small samples. [5]

  6. High blood pressure, added to drugs

    Insufficient evidence

    17 trials (1,460 people) favored the add-on for blood pressure and mood scores; the review said efficacy and safety remain uncertain. [6]

Well-designed blinded trials are still needed, and pooled numbers from low-quality trials may overstate benefit.

Frequently asked questions

What is Xiao Yao San made of?

A trials review lists eight components: Bupleuri, Angelicae Sinensis, Paeoniae Alba, Atractylodis Macrocephalae, Poria, Menthae Haplocalycis, fresh ginger and licorice. [1]

Where does it come from?

The review dates its record to the Taiping Huimin Heji Jufang (1078 to 1085 AD) of the Song dynasty. [1]

Does it work for depression?

Reviews found better scores when it was added to antidepressants, but certainty was low to very low and trials were small or biased. [2][3]

Is it useful for digestive problems?

A meta-analysis of 48 trials found better response than Western drugs for functional gut disorders, with limited trial quality. [1]

Is it safe with other medicines?

Unknown for many drugs. Licorice and Bupleurum both have documented cautions, so ask a pharmacist. [7][9]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Safety and interactions
  • Two of the eight ingredients carry known cautions. Licorice can raise blood pressure and cause low potassium in some people, and the US National Center for Complementary and Integrative Health (NCCIH) says small amounts of glycyrrhizin have been linked to serious effects in people at risk. [7] See also liver safety.
  • Bupleurum's saikosaponins show a dual picture: liver-protective effects in laboratory work but dose-dependent liver toxicity as well. [8] A review of herb effects on liver drug-metabolizing enzymes (CYP) flagged Bupleurum chinense as able to change drug levels. [9]
  • The qualitative synthesis reported no serious adverse events, liver toxicity or clinically significant drug interactions, but with incomplete reporting. [4] Absence of reports is not proof of safety.
  • NCCIH notes contamination and hidden-drug problems in some Chinese herbal products, and advises pregnant or nursing people to consult a provider. [10] See medication interactions.
Who should check first
Anyone on antidepressants, blood-pressure medicine, warfarin or other regularly monitored drugs should ask a clinician or pharmacist before adding it. Do not stop or change prescribed antidepressants. If you feel hopeless or think about harming yourself, call or text 988 (US Suicide and Crisis Lifeline) or your local emergency number; see stress and mood safety. Related: Chinese herbal product quality.
References
  1. Liu et al. Chinese herbal medicine Xiao Yao San in functional gastrointestinal disorders: meta-analysis and trial sequential analysis. Front Pharmacol 2022. Read 2026-10-22.
  2. Bak et al. Modified Soyo-san (Xiao-yao-san) combined with antidepressants on post-stroke depression: systematic review and meta-analysis. Front Pharmacol 2026. Read 2026-10-22.
  3. Huang B et al. Modified Xiaoyao-san for postoperative depression of breast cancer: systematic review and meta-analysis. Front Pharmacol 2026. Read 2026-10-22.
  4. Han L, Liang Q. Xiao-yao-san-type botanical drug formulations in depressive disorders: qualitative synthesis of recent human studies. Front Pharmacol 2026. Read 2026-10-22.
  5. Clinical efficacy and safety of TCM Xiao Yao San in insomnia combined with anxiety. Medicine (Baltimore) 2021. Read 2026-10-22.
  6. Efficacy and safety of Chinese herbal medicine Xiao Yao San in hypertension: systematic review and meta-analysis. Phytomedicine 2019. Read 2026-10-22.
  7. NCCIH. Licorice Root.. Read 2026-10-22.
  8. Zhu S et al. The dual role of saikosaponins in liver disease treatment. Biol Pharm Bull 2026. Read 2026-10-22.
  9. Hsieh YH, Huang ST. Interactions between cytochrome P450 enzymes and traditional Chinese herbs: a comprehensive review. J Chin Med Assoc 2026. Read 2026-10-22.
  10. NCCIH. Traditional Chinese Medicine: What You Need To Know.. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.