Reactive oxygen species (ROS) are accompanied by living organisms of more than 2 billion years. Since they constitute a serious threat to all components of the cell, in the course of evolution have developed defense systems to detoxify them. At the same time, however, appeared enzymes whose role is to deliberate ROS production under the influence of certain stimuli. Recent studies have shown that the role of the resulting RFT can be involved in the transmission of signals within the cell. The following operation will be discussed in part RFT pathways leading to activation of transcription factors and gene expression. Particular emphasis will be placed on the activation of transcription factors NF-kB and AP-1, which have a key role in the activation of a number of genes involved in inflammation and the immune response.