Methods
Literature Search
Our search was divided into a few steps. First, two investigators independently identified eligible studies from 1947 to March 2013 in MEDLINE, EMBASE and EBM Reviews using structured headings and keywords of complementary, alternative, herbal, herbs, Chinese medicine, IBD, colitis, Crohn's and proctitis. As some herbs may have slightly different names under different studies we also searched for the alternative names of each herb in Wikipedia identified in the initial search. Subsequently, a more comprehensive search was performed in six search engines (MEDLINE, EMBASE, EBM Reviews, AMED, Global Health and International Pharmaceutical Abstracts) using the name(s) of each specific herb including Tripterygium wilfordii, Wormwood, Lei gong teng, Thunder god vine, Pistacialentiscus, Aloe, Angelica sinensis, Dong quai, Female ginseng, Triticumaestivum, Common wheat, Bread wheat, Boswellia serrata, Frankincense, Plantago, Oenotherabiennis, Oenothera, Common evening primrose, Evening star, Curcumin, Turmeric and Xilei-san in combination with IBD/colitis/Crohn's/proctitis. Such a search strategy was utilised to avoid missing relevant studies. In addition, reference lists of all obtained papers were searched. Manual searches were performed for abstracts published in major international conferences, including Digestive Disease Week, United European Gastroenterology Week and Asia Pacific Digestive Week in the past 10 years, and on the bibliographies of original articles or systematic reviews with the relevant information.
Study Selection
Randomised controlled studies in which human adult IBD subjects were treated with herbal therapy were identified. For this systematic review, studies on prebiotics, probiotics[15–17] fish oils/omega 3-fatty acids,[18, 19] and moxibustion/acupuncture[20] were excluded as these therapies have been extensively reviewed recently. Studies were included if they were placebo-controlled or controlled against a conventional treatment. Only abstracts with adequate information were included. Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality. Both English and non-English papers were included. Studies were divided into those that have assessed the use of herbal therapy for the induction of remission and maintenance of remission in UC, and the induction of remission and prevention of operative recurrence for CD.
Data Collection and Extraction
Data were independently extracted into a standardised data extraction form by two independent reviewers (YTL and KKT). When discrepancies were found, a third investigator made the definitive decision for study eligibility or data extraction (SCN). All data were double-keyed into a predesigned database. Data collection included the author's name, year of publication, language of publication, study location, number of subjects, mean age of subjects, proportion of male subjects, types of herbal therapy, treatment duration, follow-up period, remission and response rates and adverse effects.