Quercetin, a polyphenolic flavonoid compound, is widely used in botanical and traditional Chinese medicine due to its potent antioxidant properties. This review highlights recent advances in the antioxidant activities, chemical research, and medicinal applications of quercetin. Quercetin's antioxidant effects are manifested through its impact on glutathione (GSH), enzymatic activity, signal transduction pathways, and reactive oxygen species (ROS). It enhances the body's antioxidant capacity by regulating GSH levels and inhibiting key enzymes such as acetylcholinesterase and butyrylcholinesterase. Quercetin also modulates various signal transduction pathways, including NRFB, AMPK, and MAPK, to improve the body's antioxidant state. Additionally, quercetin can remove ROS, protecting against oxidative damage caused by environmental factors and toxicological agents. The poor water solubility and low bioavailability of quercetin have led to studies on modifying its structure to enhance its water solubility and bioavailability, such as forming complexes with metal ions or complex ions. These modifications have shown significant improvements in the antioxidant activity and therapeutic potential of quercetin. Quercetin has been found to have potential in treating various diseases, including cancer, heart disease, depression, and poisoning-induced diseases. Its ability to influence GSH, enzymes, signal transduction pathways, and ROS production makes it a promising nutraceutical for human health. However, further research is needed to fully exploit its medicinal properties.Quercetin, a polyphenolic flavonoid compound, is widely used in botanical and traditional Chinese medicine due to its potent antioxidant properties. This review highlights recent advances in the antioxidant activities, chemical research, and medicinal applications of quercetin. Quercetin's antioxidant effects are manifested through its impact on glutathione (GSH), enzymatic activity, signal transduction pathways, and reactive oxygen species (ROS). It enhances the body's antioxidant capacity by regulating GSH levels and inhibiting key enzymes such as acetylcholinesterase and butyrylcholinesterase. Quercetin also modulates various signal transduction pathways, including NRFB, AMPK, and MAPK, to improve the body's antioxidant state. Additionally, quercetin can remove ROS, protecting against oxidative damage caused by environmental factors and toxicological agents. The poor water solubility and low bioavailability of quercetin have led to studies on modifying its structure to enhance its water solubility and bioavailability, such as forming complexes with metal ions or complex ions. These modifications have shown significant improvements in the antioxidant activity and therapeutic potential of quercetin. Quercetin has been found to have potential in treating various diseases, including cancer, heart disease, depression, and poisoning-induced diseases. Its ability to influence GSH, enzymes, signal transduction pathways, and ROS production makes it a promising nutraceutical for human health. However, further research is needed to fully exploit its medicinal properties.