Heroin is an opioid drug made from morphine, a natural substance taken from the seed pod of the various opium poppy plants grown in Southeast and Southwest Asia, Mexico, and Colombia. Heroin can be a white or brown powder, or a black sticky substance known as black tar heroin. Other common names for heroin include big H, horse, hell dust, and smack.

People inject, sniff, snort, or smoke heroin. Some people mix heroin with crack cocaine, a practice called speedballing.

Heroin enters the brain rapidly and binds to opioid receptors on cells located in many areas, especially those involved in feelings of pain and pleasure and in controlling heart rate, sleeping, and breathing.

People who use heroin report feeling a “rush” (a surge of pleasure, or euphoria). However, there are other common effects, including:

  • dry mouth
  • warm flushing of the skin
  • heavy feeling in the arms and legs
  • nausea and vomiting
  • severe itching
  • clouded mental functioning
  • going “on the nod,” a back-and-forth state of being conscious and semiconscious

People who use heroin over the long term may develop:

  • insomnia
  • collapsed veins for people who inject the drug
  • damaged tissue inside the nose for people who sniff or snort it
  • infection of the heart lining and valves
  • abscesses (swollen tissue filled with pus)
  • constipation and stomach cramping
  • liver and kidney disease
  • lung complications, including pneumonia
  • mental disorders such as depression and antisocial personality disorder
  • sexual dysfunction for men
  • irregular menstrual cycles for women

Heroin often contains additives, such as sugar, starch, or powdered milk, that can clog blood vessels leading to the lungs, liver, kidneys, or brain, causing permanent damage. Also, sharing drug injection equipment and having impaired judgment from drug use can increase the risk of contracting infectious diseases such as HIV and hepatitis (see “Injection Drug Use, HIV, and Hepatitis”).

Yes, a person can overdose on heroin. A heroin overdose occurs when a person uses enough of the drug to produce a life-threatening reaction or death. Heroin overdoses have increased in recent years.

When people overdose on heroin, their breathing often slows or stops. This can decrease the amount of oxygen that reaches the brain, a condition called hypoxia. Hypoxia can have short- and long-term mental effects and effects on the nervous system, including coma and permanent brain damage.