Evidence based medicine (EBM) addresses the question ... "What is the evidence we have to justify the treatments used in clinical practice?". See here for a fuller description of 'levels of evidence'.

Clinical trials and other types of research aim to provide evidence ("proof") whether a particular treatment works, how well it works compared to other treatments, and what are the risks of the treatment. Various organisations collate the results of clinical trials and other research to determine the evidence for various treatments and procedures.

Main sources of reviews of EBM that are often used by health professionals include:

• The Cochrane Library
• Clinical Evidence
• Bandolier

• Health Information Resources (Formerly The National Library for Health)
• NHS Evidence

• Guidelines

 CEBM - Centre for Evidence-Based Medicine

(UK site) - "The Centre has been established in Oxford as the first of several centres around the country whose aim broadly is to promote evidence-based health care and provide support and resources to anyone who wants to make use of them."

 TRIP database

(UK site) - TRIP was created in 1997 to bring together all the 'evidence-based' healthcare resources available on the Internet. It started with 1,100 links recorded from 15 sources and since then it has grown rapidly in both coverage and usability. This expansion has also encompassed the addition of new forms of material including peer-reviewed journals and 'eTextbooks', giving the site a more rounded clinical appeal.

 CEBMH - Centre for Evidence Based Mental Health

(UK site) - Promoting and supporting the teaching and practice of evidence based mental healthcare. From Oxford University.

 BMJ - Topic Collections

 NHS Centre for Reviews and Dissemination

(UK site) - Provides details of various reviews of areas of clinical practice and their effectiveness. "The majority of the CRD's dissemination activity involves raising awareness of messages from research and aims to provide important information in an easily accessible form."

You may wish to conduct your own search of the literature on a specific medical condition and its treatment by searching through Medline.