Si Wu Tang
The four-herb blood tonic that underlies most Chinese gynaecological formulas, used for irregular or painful periods. A meta-analysis of its Taohong variant in period pain is positive, but it pools small unblinded Chinese-language trials, so the result should be treated as a hypothesis.
Evidence last reviewed: August 2026
What the science says
- Taohong Si Wu Tang for primary dysmenorrhoea Limited evidence
A systematic review and meta-analysis in Explore pooled randomized trials of Taohong Siwu Tang for primary dysmenorrhoea and reported reduced pain compared with control. The primary studies were small, mostly unblinded, and used varying comparators, so the pooled effect is likely optimistic.
- Base formula itself is barely studied clinically Limited evidence
Almost all clinical work uses modified versions (Taohong, Xiangfu and others) rather than plain Si Wu Tang, and a Chinese-language research review of the Siwu series notes that mechanistic and animal work substantially outweighs clinical evidence.
- Mechanistic research is preclinical Limited evidence
Recent Si-Wu-Tang studies concern gut microbiota, liver steatosis and ovarian insufficiency in rodent models. None of these findings have been tested in people.
Dosage & safety
Scientific references
Where to buy
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