Tea is one of the most consumed beverages in the world after water. In recent years there is a growing interest in the study of its properties and its consumption is associated with healthy diets. In the present doctoral thesis, the presence of endocrine disrupters (phthalates and Bisphenol A), toxic and essential elements, and tea antioxidants were evaluated. An in vitro bioavailability study was also performed to assess the dialyzability of trace elements and antioxidants quantified in tea infusions. Liquid chromatography coupled with mass spectrometry, atomic spectroscopy, and molecular spectroscopy techniques were used to perform these studies.