Public Health Nature Is A Precondition Shishir Reza : Bangladesh is one of the mega biodiversity states in this present world and a wide variety of animal diversity is found in the wilderness areas of this country. Article 18A of the Constitution of Bangladesh deals with the protection and improvement of environment and biodiversity and provides, "The State shall endeavor to protect and improve the environment and to preserve and safeguard the natural resources, bio-diversity, wetlands, forests and wild life for the present and future citizens". The air we breathe is a product of photosynthesis by green plants; insects, worms, bacteria and other tiny organisms breaks down wastes and aid in the decomposition of dead plants and animals to enrich soils; more than 90% of the calories consumed by people in this world are produced from 80 plant species; almost 30% of medicines are developed from plants and animals. Some ecosystem services that benefit society are climate security, water purification, pollination and prevention of erosion. To feed such a large population, more land is being transformed from wilderness wildlife in agriculture, mining, lumbering and under areas for humans. Many people around the world depend on these species for their food, shelter and clothing. About 80% of our food supply comes from just 20 kinds of plants. Some of the health issues influenced by bio-diversity such as, dietary health and nutrition security, infectious disease, medical science and medical resources, social and physiological health and spiritual well being. A wide range of industrial materials are derived directly from biological resources. These include building materials, fibers, dyes, rubber and oil. It plays a part in regulating the chemistry of our atmosphere and water supply.