Quercetin, a polyphenolic flavonoid, is widely used in botanical medicine and traditional Chinese medicine due to its potent antioxidant activity. Recent studies have focused on its antioxidant effects, including its impact on glutathione (GSH), enzymatic activity, signal transduction pathways, and reactive oxygen species (ROS) caused by environmental and toxicological factors. Chemical research has mainly focused on the antioxidant activity of quercetin's metal ion complexes and complex ions. This review highlights recent advances in quercetin's antioxidant activity, chemical research, and medicinal applications. Quercetin enhances antioxidant capacity by regulating GSH levels, which helps in preventing diseases such as osteoporosis, cancer, and cardiovascular diseases. It also exhibits strong antioxidant activity when forming complexes or novel preparations. Quercetin's antioxidant effects are mediated through various mechanisms, including the regulation of enzymatic activity, signal transduction pathways, and ROS production. It has been shown to protect against oxidative damage in various tissues, including the brain, heart, and skin, and to prevent diseases such as cancer, heart disease, and depression. Quercetin's antioxidant activity is enhanced when it forms complexes with metal ions or complex ions, improving its bioavailability and antioxidant effects. These complexes have been applied in medicine and other pharmaceutical fields. Quercetin has potential therapeutic applications in treating diseases caused by oxidative stress, including those induced by toxins and environmental factors. Its antioxidant properties also make it useful in preventing and treating conditions such as diabetes, lung injury, and necrotizing enterocolitis. Despite its potential, quercetin's low solubility and bioavailability limit its pharmaceutical applications. However, modifications such as forming complexes with metal ions or complex ions, or developing new formulations like nanoparticles and polymeric micelles, have improved its solubility and bioavailability, enhancing its clinical efficacy. This review provides a comprehensive overview of quercetin's antioxidant activity, its chemical research, and its potential applications in the medicinal field.Quercetin, a polyphenolic flavonoid, is widely used in botanical medicine and traditional Chinese medicine due to its potent antioxidant activity. Recent studies have focused on its antioxidant effects, including its impact on glutathione (GSH), enzymatic activity, signal transduction pathways, and reactive oxygen species (ROS) caused by environmental and toxicological factors. Chemical research has mainly focused on the antioxidant activity of quercetin's metal ion complexes and complex ions. This review highlights recent advances in quercetin's antioxidant activity, chemical research, and medicinal applications. Quercetin enhances antioxidant capacity by regulating GSH levels, which helps in preventing diseases such as osteoporosis, cancer, and cardiovascular diseases. It also exhibits strong antioxidant activity when forming complexes or novel preparations. Quercetin's antioxidant effects are mediated through various mechanisms, including the regulation of enzymatic activity, signal transduction pathways, and ROS production. It has been shown to protect against oxidative damage in various tissues, including the brain, heart, and skin, and to prevent diseases such as cancer, heart disease, and depression. Quercetin's antioxidant activity is enhanced when it forms complexes with metal ions or complex ions, improving its bioavailability and antioxidant effects. These complexes have been applied in medicine and other pharmaceutical fields. Quercetin has potential therapeutic applications in treating diseases caused by oxidative stress, including those induced by toxins and environmental factors. Its antioxidant properties also make it useful in preventing and treating conditions such as diabetes, lung injury, and necrotizing enterocolitis. Despite its potential, quercetin's low solubility and bioavailability limit its pharmaceutical applications. However, modifications such as forming complexes with metal ions or complex ions, or developing new formulations like nanoparticles and polymeric micelles, have improved its solubility and bioavailability, enhancing its clinical efficacy. This review provides a comprehensive overview of quercetin's antioxidant activity, its chemical research, and its potential applications in the medicinal field.