Our body is constantly subjected to the environment around us..at any given point of time, we are inhaling ,swallowing and being infiltrated by micro-organisms through skin and mucous membrane ((tissue lining our gut and respiratory passages.) whether these microbes (referred to as ‘germs’ in common parlance) result in our falling sick or not,is dependent upon our body’s defense mechanism or immune system. The immune system is a complex and interactive network of our organs,cells and proteins that jointly create a defensive shield to protect our body from viruses,bacteria and any other external substances. It works continuously to kill and remove various pathogens (bacteria,virus,parasites or fungi) that manage to enter our body. The system also works to replace the body cells impacted by an illness,injury or infection. It is only when the immune system is breached that we experience bad health and illnesses. At times, it might under-perform and result in extreme infections and tumorous,etc. At the same time, an overly active immune system can cause allergies and autoimmunity diseases. The most incredible thing about our body’s immune system is its constant agility, self-evolution and awareness of the fight against bacteria or viruses that keep modifying themselves with the passage of time. There is a two-layered protection in place; INNATE IMMUNE SYSTEM- It works as a general defense against all threats posed by pathogens. ADAPTIVE IMMUNE SYSTEM- It identifies and attacks specific pathogens that the body has been previously exposed to. Both these aspects of the immune system work well in tandem and also react in the scenario of a pathogen or a harmful substance impacting the body.