Glutathione transferase Pi (GST-pi, GSTP) is known to strongly affect human susceptibility to several cancers, asthma and neurodegenerative disorders. As with other glutathione transferases, it catalyses the addition of reduced glutathione to electrophilic species, and it is important in metabolite detoxification. It also was shown to bind proteins and compounds containing iron and nitric oxide. Some of these interactions have developed in the course of evolution into regulatory pathways that back up the GST's most ancient catalytic functions and provide precise and diverse responses to chemical and redox stresses. An aim of this review is to summarise recent knowledge on GSTP's complementary functions in crosstalking pathways of conventional glutathione transfer, nitric oxide and lipid metabolism and ASK1-dependent stress response. This review will describe how these complex interactions affect regulation of cell respiration, biosynthesis of lung surfactant, organism's immunity and circadian rhythms. Integration of the data leads to a new interpretation of the role of GSTP in normal human physiology, pathology and an organism's susceptibility to diseases.