Forty studies were included: 14 placebo-controlled randomised clinical trials (RCTs, n=1,557); 12 comparative RCTs (n=3,125); four non-randomised clinical trials (n=179); six uncontrolled trials (n=1,034); and four case reports or series (n=5). Data from National Reporting Schemes based in UK, Germany, Australia, USA and at WHO, manufacturers and one herbalist organisation were included.
Adverse events reported in placebo-controlled RCTs (14 RCTs, n=1,557) included diarrhoea and other gastrointestinal problems (n=18), headache (n=6), fatigue (n=6), common cold (n=3), gastrointestinal bleeding (n=3), urinary problems (n=2), nausea (n=1) and vomiting and vertigo (n=1).
Adverse events reported in non-placebo-controlled RCTs (12 RCTs, n=3,125) included gastralgia, abdominal discomfort, hypertension, decreased libido, impotence, ejaculation disorder, gastrointestinal disorder, rhinitis, headache, fatigue, dizziness and skin disorders.
Results for other sources of data were reported.
More serious adverse events including death and cerebral haemorrhage were reported in isolated case reports or as data from spontaneous reporting schemes; the causality of the relationship to S. repens was unclear. No drug interactions were reported.