Si Jun Zi Tang (Four Gentlemen Decoction)

What it is

Si Jun Zi Tang (Sijunzi decoction, "Four Gentlemen Decoction," called Sagunjatang in Korean) is a short classical formula that many later tonic formulas are built on. This page is information only: no doses, no preparation steps, no advice to take it.

Published composition and origin

A trials review says it was first documented in the Song dynasty formula book Tai-Ping-Hui-Min-He-Ji-Ju-Fang and contains four herbs: Ginseng Radix et Rhizoma, Atractylodis Macrocephalae Rhizoma, Poria and Glycyrrhizae Radix et Rhizoma. [1] Ingredient guides: Ginseng, Poria and licorice. "Modified" Si Jun Zi Tang, with added herbs, is what many trials actually test. Some people look for it as "six gentlemen decoction"; that is Liu Jun Zi Tang, a separate formula listed separately in the research literature. [2]

How it is traditionally explained

In TCM writing, ginseng and atractylodes are described as herbs that "invigorate the spleen and replenish qi." [3] Spleen and qi here are traditional concepts, not the spleen organ as biomedicine describes it; see qi, blood and body fluids and traditional frameworks vs biomedical explanations. Laboratory studies cited by reviewers (stomach lining, gut movement, immune function) are preclinical, not proof of benefit in people. [1]

How modern practice differs

In a clinic, a practitioner rarely gives the four herbs alone. The dyspepsia review found that the benefit on response rate was limited to modified versions, which means the evidence applies to specific, customized prescriptions rather than to one fixed product. [1] A packaged patent medicine with the same name may therefore not match what was tested. Read the label (patent medicine labels) and ask a pharmacist about quality and interactions (herbal product quality).

What research measured

1. Functional dyspepsia (ongoing indigestion with no found cause)

   Insufficient evidence

   A meta-analysis of 12 randomized trials found higher response (risk ratio 1.23) and lower relapse (odds ratio 0.23) versus conventional medicines, but the response benefit was limited to modified versions and every trial was at high risk of bias. [1]

2. Melanoma chemotherapy (temozolomide)

   Preclinical

   Cell and mouse experiments only: the formula strengthened the drug's effect and reduced liver toxicity in mice. [4]

3. Asthma

   Preclinical

   A mouse study of a modified version found less airway inflammation. [5]

4. Other conditions in people

   Proper evidence not found

   We searched PubMed for randomized trials of Sijunzi decoction beyond dyspepsia and found nothing we could responsibly summarize.

Mouse results do not show that anyone should use the formula with chemotherapy. Anyone having cancer treatment should discuss any herb with their oncology team first.