Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Adverse effects
Systematic review	166 women with primary dysmenorrhoea 3 RCTs in this analysis	Adverse effects 13/97 (13%) with Chinese herbal medicine 18/69 (26%) with placebo	RR 0.81 95% CI 0.61 to 1.07		Not significant
RCT	78 women with primary dysmenorrhoea	Adverse effects (described as inner heat reaction, abnormal menses, PMS-like symptoms, respiratory disorder, and gastrointestinal disorder) with Chinese herbal medicine (Four Agents Decoction [Si Wu Tang]) for 5 days starting from the onset of bleeding or pain, for 4 cycles with placebo for 5 days starting from the onset of bleeding or pain, for 4 cycles Absolute results not reported	Statistical analysis not reported