The Cochrane Collaboration aims to help people make well-informed decisions about health care by preparing, maintaining and promoting the accessibility of systematic reviews of the effects of health care interventions. It is supported by over 650 organisations from around the world, including health service providers, research funding agencies, departments of health, international organisations, industry and universities.

The Cochrane Library is a unique source of reliable and up-to-date information on the effects of interventions in health care. Health care in the 21st century relies not only on individual medical skills, but also on the best information on the effect of each intervention being accessible to practitioners, patients and policy makers. This approach is sometimes known as "evidence based medicine". The Cochrane Library is designed to provide information and evidence to support decisions taken in health care and to inform those receiving care. Thanks to an agreement reached between the Cochrane Collaboration, which produces the library, John Wiley & Sons Ltd, the publisher of the Cochrane Library, the Health Research Board in Dublin and the Research & Development Office for the Health and Personal Social Services in Northern Ireland the Cochrane Library is now available to anyone on the island of Ireland. Please click here.

Cochrane Reviews are full-text systematic reviews, which provide an overview of the effects of interventions in health care. The reviews are highly structured and systematic. Evidence from clinical trials is included or excluded on the basis of explicit quality criteria. Each review covers a specific and well-defined area of health care. Data in reviews are often combined statistically to increase the power of the findings of numerous studies, which on their own may be too small to produce reliable results. In such cases, the review may also include graphs presenting the data from each individual study. Systematic reviews differ from other types of review in that they adhere to a strict design in order to make them more comprehensive, thus minimising the chance of bias, and ensuring their reliability. Rather than reflecting the views of the authors or being based on a partial selection of the literature (as is the case with many articles and reviews that are not explicitly systematic), they contain all known references to trials on a particular intervention and a comprehensive summary of the available evidence. The reviews are therefore also valuable sources of information for those receiving care, as well as for decision makers and researchers.

Cochrane Protocols provide information about reviews, which are currently being written. They summarise the background, the rationale and proposed methods of the review, and are published in the hope that people will comment on the plans and identify omissions or mistakes before the review is completed.

There are currently over 9000 people contributing to the work of The Cochrane Collaboration from over 80 countries. There are 50 Cochrane Review Groups, responsible for reviews within particular areas of health and collectively providing a home for reviews in all aspects of health care. These Groups are supported by 12 regional Cochrane Centres, with one based in Oxford having responsibility for helping Review Groups and individuals based in the United Kingdom and Ireland. In addition there are Methods Groups, with expertise in relevant areas of methodology; Fields or Networks, with broad areas of interest and expertise spanning the scope of many Review Groups; and a Consumer Network helping to promote the interests of users of health care. Each of these constituencies is represented on the Cochrane Collaboration Steering Group.