street drug

Etymology
This term comes from the fact that these types of substances are normally sold "on the street" by drug dealers.

Noun

 * 1)  A drug used illegally and recreationally for its euphoric and other mind-altering effects such as: opiates, cannabinoids, benzodiazepines, amphetamines and others.
 * Street drug sales are a huge problem for law enforcement since they are a magnet for gun violence and drug users.