What Is Xiao Yao San?

Xiao Yao San is a blend of herbs used for centuries in traditional Chinese medicine (TCM).

In TCM, Xiao Yao San is said to clear liver stagnation. Researchers are evaluating whether Xiao Yao San's properties benefit health conditions such as depression, post-traumatic stress disorder (PTSD), functional dyspepsia (indigestion), irritable bowel syndrome (IBS), insomnia, and more.

As an herbal blend, Xiao Yao San contains several herbs and plants. 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:

• Bupleurum root
• Chinese angelica root
• White peony root
  
• Poria mushroom
• Bighead atractylodes rhizome
• Roasted ginger
• Licorice root
• Menthol
• Peppermint

This article explores how Xiao Yao San is used in TCM. It also covers current scientific evidence on the potential uses of Xiao Yao San and possible side effects, precautions, and interactions of this ancient Chinese remedy.

Uses of Xiao Yao San

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease. 

Although few studies strongly support 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.

Depression

One animal study suggested that Xiao Yao San could help relieve depression by reducing neuroinflammation, or inflammation of the brain and spinal cord.

It is a controversial theory in which imbalances in the gut microflora are thought to contribute to neuroinflammation and, in turn, depression. According to the animal study, Xiao Yao San may help normalize imbalances in the gut, leading to improved symptoms of depression.

A 2012 review of Xiao Yao San evaluated 26 high-quality trials involving 1,837 people with depression. Researchers concluded that Xiao Yao San appeared to improve depression when taken alone or with an antidepressant. Xiao Yao San was also found to have fewer side effects than antidepressants.

A more recent review found similar results, suggesting that Xiao Yao San may be a safe and effective supplement for the treatment of depression. However, little is understood about how it may work to do so.

However, researchers believe that more rigorous studies are needed to confirm these results.

Post-Traumatic Stress Disorder (PTSD)

Xiao Yao San may help reduce anxious behaviors in people with post-traumatic stress disorder (PTSD).

One animal study found that a daily dose of Xiao Yao San lowered anxious behaviors and increased levels of allopregnanolone, a hormone in the brain. According to the study, low levels of allopregnanolone have been previously linked to PTSD symptoms. 

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

A lab-based study suggested that Xiao Yao San may counteract oxidative stress in the brain similarly to 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. 

Although animal and lab studies can be helpful, human trials regarding the effects of Xiao Yao San on PTSD are necessary to confirm these results.

Indigestion

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

One review from 2022 looked at 48 randomized controlled trials on the efficacy and safety of Xiao Yao San for gastrointestinal disorders. Researchers from the review concluded that Xiao Yao San might improve gastrointestinal disorders, like indigestion, compared to Western medicine. However, it was noted that more long-term human trials on the subject should be conducted.

Another review suggested that Xiao Yao San may be just as effective in relieving indigestion as proton pump inhibitors and prokinetic agents, two medications often used to treat indigestion.

Despite the positive findings, there was a lack of high-quality studies in these reviews. Further research should be conducted.

Irritable Bowel Syndrome

There is some evidence that Xiao Yao San may help treat irritable bowel syndrome (IBS), another gastrointestinal disorder.

Researchers from one systematic review found Xiao Yao San significantly reduced many symptoms of IBS, like abdominal pain, bloating, and diarrhea. The Chinese herb was also found to improve the overall quality of life of IBS patients who took it.

Another review confirmed these findings, concluding that Xiao Yao San may be an effective treatment for numerous gastrointestinal disorders, including IBS. In the review, Xiao Yao San alone or with medication reduced IBS symptoms, including anxiety.

Still, it is best to consult your healthcare provider before starting any new supplement or herbal preparation. Supplement use should not replace or delay the standard of care for any health condition.

Insomnia

People who have long-term insomnia can also experience anxiety and depression. Researchers conducted a meta-analysis that included nine clinical trials and 681 patients. They concluded that Xiao Yao San combined with medication and taken alone improved sleep quality.

However, due to the low-quality study design and small sample sizes, the researchers stated that more rigorous scientific clinical trials are required to further evaluate the effectiveness and safety of Xiao Yao San.

Anxiety

The same meta-analysis evaluating insomnia also analyzed the nine clinical studies for the effectiveness of Xiao Yao San in improving anxiety. The researchers concluded that Xiao Yao San combined with medication and taken alone relieved anxiety.

Again, more rigorous scientific studies are needed to confirm the effectiveness of Xiao Yao San, alone or in combination with other medication, for treating anxiety.

Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a condition where multiple cysts develop on the ovaries which lead to a cluster of symptoms including irregular menstrual cycles, acne, hirsutism (excess hair growth on the face and/or body), weight gain, and trouble sleeping. Infertility is a common complication of PCOS.

Researchers conducted a review of nine clinical trials including 736 people with PCOS and concluded that Xiao Yao San combined with conventional medicines can improve ovulation and pregnancy rates. The researchers stated that Xiao Yao San is a promising combination therapy, but larger, higher-quality clinical trials are needed to adequately assess Xiao Yao San as a complementary therapy for managing PCOS.

Although Xiao Yao San improved ovulation and pregnancy rates in this population, it is unknown whether it would have the same effect on people experiencing infertility who are otherwise healthy and do not have PCOS.

Other Uses

Although it is common for Xiao Yao San to be used in TCM for treating premenstrual syndrome (PMS) and perimenopause, there is inadequate research to determine its effectiveness for either condition, and further research is needed.

A review evaluated the effects of acupuncture and herbal medicine on PMS. Although acupuncture and herbal medicine treatments for premenstrual syndrome showed a 50% or better reduction of symptoms, the herbal medicine included six different herbs, Xiao Yao San being one of them. Therefore, it isn't possible to determine the effectiveness of Xiao Yao San specifically for treating PMS.

What Are the Side Effects of Xiao Yao San?

Xiao Yao San is generally regarded as safe. However, consuming Xiao Yao San may have potential side effects.

Common Side Effects

Few side effects of Xiao Yao San have been reported, and most studies on the herbal remedy tout it as safe.

Reported side effects of Xiao Yao San include:

• Headache
• Dizziness
• Diarrhea
  

Other studies and reviews have reported little to no side effects of Xiao Yao San. Typically, possible side effects are mild and should resolve with time.

To best avoid side effects, use Xiao Yao San only as directed.

Severe Side Effects

Severe side effects of Xiao Yao San have not been reported.

A meta-analysis found no severe side effects or adverse events out of 48 randomized controlled trials on Xiao Yao San.

Although severe side effects have not yet been reported, they may still be possible. Talk with your healthcare provider about how to use Xiao Yao San safely.

Precautions

The precautions of Xiao Yao San are not well documented. But like with any herb or supplement, Xiao Yao San may not be safe for some people.

Xiao Yao San contains many herbs and active ingredients, some of which may not be suitable for certain populations.

For example, licorice root, an active ingredient of Xiao Yao San, is not recommended for pregnant people or those with kidney disease or high blood pressure. However, there are no guidelines on whether Xiao Yao San is safe for these populations.

Talk with your healthcare provider before starting Xiao Yao San, especially if you have these or other health conditions.

Dosage: How Much Xiao Yao San Should I Take?

There is no universal recommended dose for Xiao Yao San. Therefore, Xiao Yao San brands may have different dosage instructions.

To take Xiao Yao San safely, follow dosage guidelines on the product label or as recommended by your healthcare provider.

What Happens If I Take Too Much Xiao Yao San?

Xiao Yao San is not thought to be toxic. There are no documented reports of toxicity or overdose for Xiao Yao San.

Keep in mind, however, that you may be more likely to experience side effects if you take more Xiao Yao San than recommended.

To avoid potential side effects, only take Xiao Yao San as directed.

Interactions

Xiao Yao San may interact with certain medications, supplements, and foods. However, possible interactions are not well documented. This means it's unknown which medicines, supplements, and foods may interact with Xiao Yao San.

Before starting Xiao Yao San, tell your healthcare provider what medications and other supplements you are taking.

It is vital that you carefully read the ingredient list and nutrition facts panel of a new supplement to know which ingredients and how much of each ingredient is included. Please take precautions and review any new supplement labels with your healthcare provider to discuss any potential interactions with foods, other supplements, and medications. 

How to Store Xiao Yao San

It's important to properly store supplements to keep them fresh.

Xiao Yao San supplements should be stored in a cool, dry place. They should also be kept out of direct sunlight. It is typically not necessary to refrigerate Xiao Yao San.

You should throw away Xiao Yao San supplements after they have reached their expiration date.

Similar Supplements

Xiao Yao San has many potential uses and may work similarly to other supplements. However, you should only take one supplement at a time for a single health condition. Talk with your healthcare provider about the best option for you.

Supplements being studied for similar uses to Xiao Yao San include:

• Saffron: A perennial herb, saffron may benefit those living with depression. In a small human trial, researchers found that taking saffron could improve subclinical symptoms of depression. Results from the study revealed that, compared to a placebo, healthy adults with low mood who took 30 milligrams (mg) of saffron for 56 days had improved social relationships and greater reductions in the depression scale.
• Vitamin D: Low vitamin D levels in the blood have been linked to developing post-traumatic stress disorder (PTSD). Because of this link, some researchers have suggested that combat soldiers with a vitamin D deficiency should use supplements to reduce their risk of PTSD.
• Melatonin: Melatonin may be able to do more than help you sleep. A hormone produced by the brain, melatonin has been shown to improve symptoms of indigestion, including acid reflux.
• Psyllium: A type of soluble fiber, psyllium is a potential supplement option for those with IBS. According to one review, psyllium supplements have documented proof of improving the overall symptoms of IBS.
  

Sources of Xiao Yao San & What to Look For

Xiao Yao San is best consumed in supplement form. There are many things to consider when shopping for Xiao Yao San.

Since Xiao Yao San is a mixture of many herbs, it is not naturally found in foods. And while you may find some of the ingredients of Xiao Yao San in foods, not all are commonly found in food form.

Fortunately, there are many options for Xiao Yao San supplements.

Xiao Yao San Supplements

Xiao Yao San supplements are available as capsules, tinctures, and tea pills (herbal extracts compressed into pea-sized balls). These can easily be found online, at many natural food stores, and in specialty herbalist shops.

Xiao Yao San supplements are sometimes sold under different brand names, including Free and Easy Wanderer, Relaxed Wanderer, or Rambling Powder.

It's important to note that dietary supplements are not regulated as strictly as conventional foods and medications in the United States. According to the National Center for Complementary and Integrative Health, supplements imported from China pose additional risks, as the ingredients are written in a different language and may contain heavy metals, drugs, and other contaminants.

When choosing a supplement, look for products 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.

Summary

Xiao Yao San is a mixture of herbs commonly used in traditional Chinese medicine to treat various health conditions, including depression, PTSD, indigestion, and IBS. Xiao Yao San is generally considered safe and has few reported side effects.

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

Consult your healthcare provider or a licensed TCM practitioner before taking Xiao Yao San. Remember that supplements should not serve as a replacement for standard medical care for any health condition.