This report presents the findings from the eighteenth year in which data has been collected in South Australia (SA). The Ecstasy and Related Drugs Reporting System (EDRS) monitors the price, purity and availability of ‘ecstasy’ (MDMA) and other drugs such as methamphetamine, cocaine, gamma-hydroxybutyrate (GHB), ketamine, dlysergic acid (LSD), and 3,4-methylendioxyamphetamine (MDA). It also examines the demographic characteristics and patterns of drug use among people who use stimulants regularly, the prevalence of risk-taking and harms related to drug use, as well as the level of criminal involvement among this group. It utilises data from two sources: (a) surveys with people who use stimulants regularly; and (b) the analysis of existing data sources that contain information on ecstasy and related drugs (ERD). The EDRS surveys are not representative of people who use stimulant drugs in the general population. The EDRS sample is a sentinel group that provides information on patterns of drug use and market trends.