This is a state of hypersensitive reaction in an individual to a particular substance, called the `allergen'. The allergen produces a characteristic response, whenever the person is exposed it. Symptoms usually develop rapidly, depending on the nature of the allergy. Common symptoms are skin reactions, swelling and puffiness, wheezing and breathing difficulties, headaches, stomach pain and diarrhoea.

Generally the immune system should be strong enough to avoid any allergic reaction of the body. The immune system workout given in the appendix, done daily for a few months, will help to enhance immunity.