Xiao Chai Hu Tang (Minor Bupleurum Decoction) is one of the most studied and frequently prescribed classical formulas in East Asian medicine. Composed of seven ingredients — bupleurum, scutellaria, pinellia, ginger, ginseng or codonopsis, jujube, and honey-fried licorice — it was first recorded by Zhang Zhongjing around 200 CE as a treatment for 'shao yang syndrome,' a mid-stage illness pattern marked by alternating fever and chills, bitter taste, and chest discomfort. Today it remains one of the top-prescribed Kampo formulas in Japan and is used widely across China, Korea, and Taiwan.

The formula works through multiple pathways at once: bupleurum and scutellaria together calm immune overactivation and reduce inflammatory signaling, while pinellia and ginger settle nausea and support digestive motility. Ginseng, jujube, and licorice tonify energy and help the body mount a balanced immune response rather than an excessive one. This combination is thought to work at the interface between the immune and digestive systems — which is why it benefits both liver conditions and lingering respiratory illness.

The traditional form is a water decoction brewed from raw herbs. Modern versions most commonly come as spray-dried granule powders that dissolve in hot water, making them practical for daily use. Capsule and tablet forms are also widely available but may deliver slightly lower potency than granules or decoctions. In Japan, the standardized extract TJ-9 (Tsumura brand) has been used in clinical trials and is the most studied commercial form.

• Chronic hepatitis (B and C)
• Liver inflammation and elevated enzymes
• Lingering cold and flu / post-viral fatigue
• Nausea and digestive discomfort
• Low-grade fever that won't resolve
• Immune system dysregulation
• Mild depression and irritability linked to illness
• Chronic fatigue with digestive symptoms
• Respiratory infections (early to mid-stage)

• Liver fibrosis progression in chronic hepatitis (supported by Japanese clinical trial data suggesting reduced fibrosis rates with long-term use)
• Hepatocellular carcinoma risk reduction in cirrhotic patients (observed in observational data, though a large RCT found no benefit and possible harm in interferon-treated patients — this claim requires careful interpretation)

• Bitter melon
• Artichoke
• Ginger root (fresh or tea)
• Miso soup and fermented soy foods
• Jujube (red dates)

• Nausea or mild stomach upset (usually transient, take with food)
• Loose stools or diarrhea at higher doses
• Allergic skin reactions (rare)
• Interstitial pneumonia — rare but serious; watch for new or worsening cough or shortness of breath and seek medical attention promptly
• Fluid retention or elevated blood pressure with prolonged use (due to glycyrrhizin in licorice)
• Potassium depletion with extended high-dose use
• Liver enzyme elevation in rare cases of idiosyncratic reaction (paradoxical, given the formula's liver-protective intent)

• Recommended daily: Granule powder (standardized extract): 7.5–9 g per day divided into 2–3 doses. Traditional decoction: 1 packet of raw herbs (approx. 100–120 g combined) simmered to yield 400–600 mL, divided into 2–3 cups daily. Follow product label or practitioner guidance, as concentrations vary by brand.
• Best time of day: Traditionally taken in 2–3 divided doses spread through the day. Morning and evening dosing is most common in modern Kampo practice.
• With or without food: Classically taken 30 minutes before meals or between meals on an empty stomach for best absorption. If stomach sensitivity occurs, taking with a small amount of food is acceptable.
• Time to effect: Acute illness symptoms (fever, nausea): 1–5 days. Liver enzyme normalization and chronic conditions: 4–12 weeks of consistent use.
• How long to take it: For acute illness: short course of 5–14 days. For chronic liver conditions or immune support: 3–6 month courses are common in clinical practice, with periodic reassessment by a practitioner. Not recommended for indefinite unsupervised use due to licorice content.