Plant phenolics are widely distributed in the plant kingdom and are the most abundant secondary metabolites. They are known for their potent antioxidant and anticancer properties, making them a focus of health and medical research. This review discusses the extraction, analysis, and biological activities of plant phenolics, including their antioxidant and anticancer effects. Phenolics are involved in plant defense against UV radiation and pathogens, and are present in various plant foods and beverages. They contribute to the flavor, color, and organoleptic properties of plant-based foods. Phenolics include phenolic acids, flavonoids, tannins, stilbenes, and lignans. Flavonoids are the most abundant polyphenols in the diet, with various subgroups such as flavones, flavonols, flavanols, flavanones, isoflavones, and anthocyanins. Phenolic acids include derivatives of benzoic and cinnamic acids, such as gallic, caffeic, and ferulic acids. Tannins are divided into hydrolysable and condensed tannins, with structures varying based on the type of linkage and chemical composition. Phenolic compounds are extracted from plant materials using various methods, including solvent extraction, microwave-assisted extraction, ultrasound-assisted extraction, and pressurized liquid extraction. The choice of solvent and extraction conditions significantly affects the yield and quality of phenolic compounds. Purification and fractionation techniques such as solid-phase extraction, column chromatography, and countercurrent chromatography are used to isolate and identify phenolic compounds. Analysis of phenolics involves methods like Folin-Ciocalteu assay, UV-Vis spectroscopy, HPLC, and other chromatographic techniques to quantify their antioxidant capacity and structure. Phenolic compounds exhibit antioxidant properties by scavenging free radicals, chelating metal ions, and enhancing antioxidant defense systems. However, some phenolics can also act as prooxidants under certain conditions, initiating autoxidation reactions. The total antioxidant capacity (TAC) of phenolic extracts is determined using assays such as TEAC, ORAC, TRAP, FRAP, and CUPRAC. These methods help assess the overall antioxidant potential of phenolic compounds, which is crucial for evaluating their health benefits. The review highlights the importance of proper extraction, purification, and analytical methods in understanding the biological activities of plant phenolics.Plant phenolics are widely distributed in the plant kingdom and are the most abundant secondary metabolites. They are known for their potent antioxidant and anticancer properties, making them a focus of health and medical research. This review discusses the extraction, analysis, and biological activities of plant phenolics, including their antioxidant and anticancer effects. Phenolics are involved in plant defense against UV radiation and pathogens, and are present in various plant foods and beverages. They contribute to the flavor, color, and organoleptic properties of plant-based foods. Phenolics include phenolic acids, flavonoids, tannins, stilbenes, and lignans. Flavonoids are the most abundant polyphenols in the diet, with various subgroups such as flavones, flavonols, flavanols, flavanones, isoflavones, and anthocyanins. Phenolic acids include derivatives of benzoic and cinnamic acids, such as gallic, caffeic, and ferulic acids. Tannins are divided into hydrolysable and condensed tannins, with structures varying based on the type of linkage and chemical composition. Phenolic compounds are extracted from plant materials using various methods, including solvent extraction, microwave-assisted extraction, ultrasound-assisted extraction, and pressurized liquid extraction. The choice of solvent and extraction conditions significantly affects the yield and quality of phenolic compounds. Purification and fractionation techniques such as solid-phase extraction, column chromatography, and countercurrent chromatography are used to isolate and identify phenolic compounds. Analysis of phenolics involves methods like Folin-Ciocalteu assay, UV-Vis spectroscopy, HPLC, and other chromatographic techniques to quantify their antioxidant capacity and structure. Phenolic compounds exhibit antioxidant properties by scavenging free radicals, chelating metal ions, and enhancing antioxidant defense systems. However, some phenolics can also act as prooxidants under certain conditions, initiating autoxidation reactions. The total antioxidant capacity (TAC) of phenolic extracts is determined using assays such as TEAC, ORAC, TRAP, FRAP, and CUPRAC. These methods help assess the overall antioxidant potential of phenolic compounds, which is crucial for evaluating their health benefits. The review highlights the importance of proper extraction, purification, and analytical methods in understanding the biological activities of plant phenolics.