Camellia sinensis (L.) Kuntze is a small tree of the family Theaceae, of Asian origin, well adapted to cultivation in Brazil. The consumption of black tea, made from the infusion and complete fermentation of the leaves of this plant, is culturally carried out in the east and the west. This study aims to, through a review, relate the presence of certain chemical groups present in tea with the antioxidant therapeutic effects caused by its consumption. A high concentration of polyphenols (3 to 20%) was identified in black tea, among them catechins such as epicatechin (EC), galatocine gallate (ECG), epigallocatechin (EGC) and epigallocatechin gallate (EGCG). The polyphenols present in the fermented tea of ​​Camellia sinensis are reported to be responsible for the antioxidant effects produced by tea. In vivo studies have identified the effective ability of polyphenols to inhibit lipid peroxidation and cause upregulation of the endogenous antioxidants SOD, GST, GHS, GR, CAT and GPx. Preventing the exaggerated formation of free radicals, thus contributing to the reduction of the risk of cancer and neurodegenerative diseases. Therefore, promoting in-depth studies on the therapeutic effects of black tea is a promising method for the development of treatments related to cancer and other diseases caused by oxidative stress.