Computer graphics space-filling representation of an amphetamine molecule, a drug with stimulant and appetite-depressant properties. Since the 1960's amphetamine (in powdered sulphate form) has been abused as a stimulant, being ingested by sniffing or injection. The prescription of amphetamines in the UK is controlled by law and usually restricted for use as an appetite depressant in people suffering from obesity. Colour coding: green - carbon atoms; white - hydrogen atoms; dark blue - nitrogen atoms.