Idiosyncratic toxicity is a rare adverse drug-induced reaction. It may occur in a small number of patients, is often serious and may lead to patients' death. Preclinical and clinical drug development fail to predict idiosyncratic post-marketing problems. Idiosyncratic adverse reaction could be prevented either by detection of predisposed patients or use of biomarkers that could predict adverse reactions induced by a drug. The identification of biomarkers that could help predict idiosyncratic reaction requires highthrouhput technologies such as << omics >> (genomic, transcriptomic, proteomic, metabonomic), which are methods allowing screening and evaluation of extensive data and are suitable for untargeted analyses of different models. This review presents genomic and transcriptomic data. The genomic studies identified genetic risk factor that could be used in clinical practice to prevent idiosyncratic reaction in predisposed patients. The transcriptomic studies gave information on biological processes altered by a treatment with a drug. Understanding toxicity mechanisms could lead to identification of toxicity biomarkers.