Chemicals and drugs are both artificially created materials which are made in a laboratory. A "chemical" is any term for a collection of atoms, and usually describes a compound which has been designed by scientists for a specific purpose. In fact, all manufactured drugs are actually a type of chemical compound of a specific kind, which has been designed to have a specific type of effect on the human body. "Drugs" is a rather generic term and may be applied to any type of medication which is prescribed by doctors or a medical professional. Today it may be more commonly used to refer to illegal chemicals which are taken for recreational purposes. Drugs commonly available on the streets include marijuana, cocaine, heroin and amphetamines.