Heroin is a highly addictive, illegal drug. It is used by millions of addicts around the world who are unable to overcome the urge to continue taking this drug every day of their lives—knowing that if they stop, they will face the horror of withdrawal. Heroin (like opium and morphine) is made from the resin of poppy plants. Milky, sap-like opium is first removed from the pod of the poppy flower. This opium is refined to make morphine, then further refined into different forms of heroin. Most heroin is injected, creating additional risks for the user, who faces the danger of AIDS or other infection on top of the pain of addiction.