Objectives:Using food to prevent diseases has become the focus of different researchers in recent years. Tea is a natural source of caffeine, flavonoids, ascorbate, theanine, and antioxidants. The purpose of this study was to provide a review of the benefts and harms of tea for different body systems. 

Methods and Materials:The present review study was conducted by searching through the websites and assessing the results in the literature using a library research method. The data were collected for publications during 2000-2018.

Results: Various epidemiological studies concluded that tea and its polyphenolic contents have benefcial effects on different bodily systems including the cardiovascular system, diabetes control, and different types of cancer. However, some studies argue that tea may have harmful effects on the bodily systems.

Conclusions:Overall, tea is considered benefcial to human health. It can also be recommended as a healing beverage. Nevertheless, conflicting fndings are reported about the risks of tea as well. Therefore, more studies are needed to further explore the benefts and possible harms of different types of tea.