A Natural pesticide is a substance that disrupts or kills organisms that we consider to be pests such as weeds, damaging insects, or microbes that cause disease. Pesticides that are made by other organisms, usually for their own defense or that comes from a natural source like a mineral or a plant are called natural pesticides. Although this is generally true, not all natural pesticides are always safer or better for the environment than man-made pesticides. Nicotine, for instance, is the highly addictive component of cigarette smoke and a natural pesticide found in tobacco leaves, but it is actually much more toxic than the majority of modern synthetic pesticides.