This review deals with different aspects of driving under the influence of drugs (DUID).Cannabis, cocaine, opiates, amphetaminesand methamphetamines are the most prevalent illegal drugs detected in the surveys carried out by the police and involved in traffic accidents. The use of oral fluid matrix to detect drugged drivers as well as pharmacokinetics of illegaldrugs in oral fluid, correlation with blood, times of elimination and on-site drugs tests has been considered. A brief description of the marketed on-site test devices is provided. The relationship between drug use and impairment driving, andarticles published in the specialized literature have been consulted. Data has been obtained from MEDLINE base date duringthe last years. Although oral fluid is a suitable fluid for analysis and the a steady progress has been done along the time, in the devices for screening, more effort must be achieved regarding to its performance and reliability regarding to parametersas sensibility specificity and recovery, specially for cannabis, the most prevalent drug detected. Standardized protocols referringto sample collection, established cut-offs, analytical confirmatory methods are issues that may be established to avoid erroneous results and interpretation. At present, legislation around the world using the oral fluid in legal procedure is notwell defined but some countries are applying these methods to sanction drivers. In Spain, in Catalonia region, qualitativeresults are being utilized to fine drivers and courts are admitting the proofs.