Aims The aim of this systematic review was to assess the published clinical evidence
on interactions between herbal and conventional drugs.
Methods Four electronic databases were searched for case reports, case series or clinical
trials of such interactions. The data were extracted and validated using a scoring system
for interaction probability.

Systematic reviews and meta-analyses represent the uppermost ladders in the hierarchy of evidence. Systematic
reviews/meta-analyses suggest preliminary or satisfactory clinical evidence for agnus castus (Vitex agnus castus)
for premenstrual complaints, flaxseed (Linum usitatissimum) for hypertension, feverfew (Tanacetum

The focus of the great majority of climate change impact studies is on changes in mean climate. In terms of climate model output, these changes are more robust than changes in climate variability. By concentrating on changes in climate means, the full impacts of climate change on biological and human systems are probably being seriously underestimated.