Systematic literature searches were made using Medline
(via PubMed, from January 1966 to February 2003). The
search terms were herbal medicine, botanical medicine,
phytotherapy, drug interaction, adverse effects, side effects,
adverse drug reaction, safety and toxicity. Recent books on
herb–drug interactions or herbalism [21–26] were also
searched for further relevant information. Additional publications
were identified by checking all reference lists and
by searching our files. No language restrictions were imposed.
All clinical reports on interactions were read and
relevant data were extracted by the first three authors into
predefined tables and validated by the senior author. In vitro
experiments have been excluded.