In the past few years the world has been witnessing epidemics, one after another. First was SARS, bird flu and now the swine flu. Before 60, 7 0 years it was acceptable, man had no control over infectious diseases. But today when medical science has advanced to the extent of making clones, why should man suffer/ die from some infectious disease, particularly in developed countries, where advanced medical facilities are available? To find the answer, man needs to do some introspection. Nature has provided every living being with some defence mechanism called immune system. This happens to be most advanced in human beings. A human body can recognize foreign harmful substances entering the body and tries to eliminate or contain them. There are mechanical means like coughing, sneezing and sweating to expel foreign substances. All body secretions like saliva, tears, semen, vaginal fluid, e.t.c. contain chemicals which protect against harmful germs. Now in spite of this strong defence system, mankind is suffering from infectious diseases. There are some diseases like chronic renal failure, HIV/AIDS which reduce the immunity of the body. Malnutrition, particularly protein deficiency, reduces the body’s immunity. Deficiency of vitamins like Vitamin C, folic acid, essential micronutrients like zinc, copper, selenium is also responsible for reduced immunity in the body. Obesity which is another aspect of malnutrition is also said to derange the immune system. Smoking also impairs the immunity by causing chronic irritation. Drugs like corticosteroids, antimitotics, used to suppress inflammation, to prevent auto immune reactions or treat cancers, retard the disease process but also damage the immune system. With all round scientific development in the past 50 or 60 years, there has been much exposure of man to different kinds of chemicals. In some way these chemicals have added to the physical comforts but now scientists are being alarmed as the harmful effects of these chemicals are coming forward. Pesticides used to kill pests in gardens and fields are harmful in many ways and damage the immune system. Chemicals added to processed foods like antibiotic and hormone treated meat products, preservatives used in various “fast ready to eat” foods, have been proved to be harmful. Mattresses made of vinyl and polyurethrane foam, are not only harmful for the back but also for the immune system of the body. They emit toxic chemicals which produce allergy, aggravate asthma and are also carcinogenic. Long term exposure to low dose radiation emitted from daily use instruments like microwave ovens, mobile phones, e.t.c. also has the potential to damage the lymphocytes of the body (cells involved in immunity) and lead to various kinds of diseases. Of course exposure to high doses of radiation is definitely harmful for the immune system. Good sleep is essential for boosting the immune system, but stress of modern city life has deprived many people of their sleep thus reducing the immunity too. A balanced nutritious diet including proteins, essential fatty acids, particularly omega 3 fatty acids, essential micronutrients is useful to maintain and boost the body’s immune system. Fresh vegetables, fruits, fish, garlic, honey are some of the food substances that are very useful in this regard. “Going organic”’ is the mantra of the day to avoid harmful effects of chemicals. Advice given by experts is to grow your own vegetables and fruits in the kitchen garden. This ensures fresh vegetables which are most healthy and also provides opportunity to do some much needed physical work. Manure and pesticides used should be organic, i.e. not chemical. One should avoid fast and processed foods. Try to consume food prepared from scratch, i.e. absolutely fresh. Deep fried foods like French fries, e.t.c. are not healthy and should be used only once in weeks or months. Plastics and polythene are harmful for the environment as well as human health and are rightfully banned by the Rwandan Government. Much stress is being laid in developed countries on use of organic products in cosmetics, clothes, bedding, e.t.c to avoid harmful effects of synthetic products. There is no substitute for a disciplined healthy life for improving the immune system, which includes adequate physical exercise, balanced diet and a stress free mind.True advancement in medical science will occur when man has conquered all kinds of infections. The author is a specialist in Internal MedicineE-mail: rachna212002@yahoo.co.uk