Facts about how heroin is used covers inhalation, injection, smoking, and other means such as oral ingestion. In the past, heroin was primarily used by injection. Today users are ingesting heroin in other ways which are just a dangerous and deadly.

In the U.S.A the Harrison Narcotics Tax Act was passed in 1914 to control the sale and distribution of heroin and other opiates. The law did allow heroin to be prescribed and sold for medical purposes. In particular, recreational users could often still be legally supplied with heroin and use it. In 1924, the United States Congress passed additional legislation banning the sale, importation or manufacture of heroin in the United States. It is now a Schedule I substance, and is thus illegal in the United States.

Often these heroin users are under the misconception that if they do not inject the drug they will not become addicted. Those who have entered rehab to recover from heroin addiction include every method of heroin user. Annual admissions to substance abuse treatment for primary heroin abuse increased from 228,000 in 1995 to 254,000 in 2005; however, the proportion of primary heroin admissions remained steady at about 14 to 15 percent of all admissions. Between 1995 and 2005, inhalation and injection accounted for at least 94 percent of annual primary heroin admissions.

Major withdrawal symptoms peak between 48 and 72 hours after the last dose and typically subside after about a week; however, some individuals may show persistent withdrawal symptoms for months. Although heroin withdrawal is considered less dangerous than alcohol or barbiturate withdrawal, sudden withdrawal by heavily dependent users who are in poor health is occasionally fatal.