The difference between a drug and a illegal drug?

An illegal drug is a drug which is prohibited by the law. An example of this is cannabis, a popular illegal drug. If you were caught supplying illegal drugs you could get a lengthy sentence. Up to a life sentence for supplying and about 3-7 years for possession. A normal drug is a drug that is normally legal or prescribed. Coffee is a legal drug. The difference is that one of the drugs will put you in prison and one won't.