Heroin is a depressant drug that comes from the poppy plant. It was legal in the United States until the 1920s. Using heroin can lead to serious health risks depending on the method of ingestion. When injected, snorted, or taken orally as pills, heroin use may cause HIV, AIDS, STDs, heart failure, overdose, and death. It is important to avoid interacting with anyone offering or possessing heroin and to remove oneself from situations involving heroin use.