The Ecstasy and related Drugs Reporting System (EDRS; formerly the ‘Party Drugs Initiative’) is a study that monitors trends and issues emerging from illicit drug markets in Australia. The data collected examines the price, purity and availability of four primary illicit drug classes – ecstasy, methamphetamine, cocaine and cannabis as well as niche market drugs such as GHB and LSD. People who regularly use stimulants have been identified as a sentinel group and provide information on patterns of use, market characteristics, related harms and other issues associated with ERD use.