It is a broad term that refers to a variety of substance that has varying effects on people – medicinal, intoxicating or enhancing. They can include medicines, recreational drugs and performance enhancing ones. In the last century, medicinal drugs have become essential for human survival and longevity. It has become standard practice around the world to take vaccinations (preventive medicine) to increase immunity against diseases. On the other hand, the use of recreational drugs is extremely troublesome for society with the legal ones (tobacco and alcohol) causing far more damage than the illegal ones (cannabis, heroin, hallucinogens and other narcotics).