Background: Theoretically, doctors update their knowledge from the scientific literature, and bibliographic databases have made it possible to overcome many of the limitations with this information, but not all of them. When faced with a therapeutic issue, the practice of evidence based medicine requires the efficient access to information derived from controlled clinical trials (CCT). Reviews of the scientific literature are of increasing importance. The Cochrane Collaboration is dedicated to preparing, maintaining and disseminating updated, systematic reviews of CCTs of health care interventions, which are published in the Cochrane Library.

Objective: To describe the Cochrane Collaboration and to locate, with the greatest exhaustiveness possible, CCTs published in the journals "Enfermedades Infecciosas y Microbiología Clínica", describe their characteristics and include them in a global database of clinical trials maintained by the Cochrane Collaboration.

Methods: The CCTs were identified by systematic manual searches of all issues of the journal. A descriptive analysis of the CCTs located was made.

Results: A total of 24 CCTs were published in 15 years (1.6 per year), 10 were original articles and 14 were communications at congresses. All were done in Spain and the majority were done in hospitals. The most frequently researched question was antibiotic prophylaxis and all evaluated pharmaceutical interventions. The majority of the CCTs published had important information missing (phase of study, randomization, blinding, etc.).

Conclusions: The identification of CCTs is a prerequisite for the development of systematic reviews. There were few clinical trials published in the 15 years of publication of this journal, and the most common characteristic is, clearly, the absence of basic data. The most common is a lack of on the phase of the clinical trial, the follow-up period, and funding sources. The idea of what experimental clinical investigation in infectious diseases is in our country needs to include the identification of CCTs published in other Spanish and international journals.