SummarySelective digestive decontamination (SDD) is a method that aims to eradicate the oropharyngeal and gastrointestinal carriage of potentially pathogenic micro-organisms (PPMO) by means of the application of high oropharyngeal and faecal antimicrobial concentrations. The SDD technique has proven its effectiveness in patients with profound granulocytopenia and has become commonplace in most European haematological services. A large number of trials most often uncontrolled or relying on historical controls have evaluated the use of SDD in intensive care patients.This article gives a summary of the effects of SDD on: colonisation of the different mucosae, infection, hospitalisation-time, mortality, cost-benefit aspects and the selection of resistant micro-organisms.