Reactive oxygen species (ROS) are highly reactive intermediates of oxygen formed during successive reduction ofoxygen. Most common ROS include singlet oxygen 1O2, Superoxide (O2•−), Hydrogen Peroxide (H2O2), and Hydroxylradical (•OH). ROS are produced as by-products of normal aerobic metabolism in plants. However, during biotic orabiotic stress conditions ROS greatly increase in number causing oxidative stress. The highly reactive nature of thesespecies poses a problem for cellular metabolism. Oxidative damage caused by ROS can even lead to cell death. As theproduction of ROS is inevitable, plants have evolved means to eliminate ROS and maintain a reducing environment inthe cell. These strategies involve antioxidant enzymes as well as non-enzymatic antioxidant compounds. Two systemswork together to neutralise reactive species and protect the cell from oxidative injury. A useful aspect of ROS has alsobeen observed in that they act as second messengers in signalling. Ultimately, it is important to maintain equilibriumbetween the production and removal of ROS for a healthy cellular environment. This review deals with mechanisms ofproduction of ROS and strategies of a plant cell to scavenge them.