This review article by Volodymyr I. Lushchak focuses on the multifaceted roles of glutathione (GSH) in biological systems and its potential as a target for medical interventions. GSH, a tripeptide, plays a crucial antioxidant role by interacting with reactive oxygen and nitrogen species (ROS and RNS) and electrophiles. The article provides an updated overview of GSH's biosynthesis, hydrolysis, and utilization, as well as its intracellular compartmentalization and interorgan transfer. It highlights GSH's involvement in detoxifying endogenous and exogenous toxicants, maintaining metal homeostasis, and regulating enzymes through glutathionylation of sulphydryls. The review also discusses the relationship between GSH homeostasis and various pathologies, and explores pharmacological approaches to manipulate GSH levels, particularly through natural compounds. The Nrf2/Keap1 pathway is highlighted as a key regulatory mechanism that controls the expression of GSH-related enzymes, emphasizing its importance in both physiological and pathological contexts. Overall, the article provides insights into the molecular mechanisms of GSH's functions and suggests potential therapeutic strategies targeting GSH for the treatment of diseases.This review article by Volodymyr I. Lushchak focuses on the multifaceted roles of glutathione (GSH) in biological systems and its potential as a target for medical interventions. GSH, a tripeptide, plays a crucial antioxidant role by interacting with reactive oxygen and nitrogen species (ROS and RNS) and electrophiles. The article provides an updated overview of GSH's biosynthesis, hydrolysis, and utilization, as well as its intracellular compartmentalization and interorgan transfer. It highlights GSH's involvement in detoxifying endogenous and exogenous toxicants, maintaining metal homeostasis, and regulating enzymes through glutathionylation of sulphydryls. The review also discusses the relationship between GSH homeostasis and various pathologies, and explores pharmacological approaches to manipulate GSH levels, particularly through natural compounds. The Nrf2/Keap1 pathway is highlighted as a key regulatory mechanism that controls the expression of GSH-related enzymes, emphasizing its importance in both physiological and pathological contexts. Overall, the article provides insights into the molecular mechanisms of GSH's functions and suggests potential therapeutic strategies targeting GSH for the treatment of diseases.