Common street names: Big H, Black Tar, Chiva, Hell Dust, Horse, Negra, Smack

Heroin is processed from morphine, which is a naturally occurring substance extracted from the seed pod of certain varieties of poppy plants grown primarily in Southeast Asia, Southwest Asia, Mexico, and Colombia. 

Heroin is typically sold as a white or brownish powder, or as a black sticky substance known as "black tar".  Most street heroin is cut with other drugs or substances such as starch, sugar, quinine, or powdered milk.

Heroin can be injected, smoked, sniffed, or snorted.  It is particularly addictive because of the rapid speed with which it enters the brain.  Heroin users report feeling euphoria or a rush followed by a dreamy state of wakefulness and sleep.  Physical symptoms include drowsiness, respiratory depression, constricted pupils, nausea, a warm flushing of the skin, dry mouth, and heavy extremities.

There is a high risk overdose since users do not know the strength or potency of the drug or its true contents as it is often mixed or cut from fentanyl or other substances.  Effects of an overdose are slow and shallow breathing, blue lips and fingernails, clammy skin, convulsions, coma, and possibly death.

Drugs which have similar effects as heroin include other opioids such as Oxycontin, codeine, morphine, methadone, and fentanyl.