Gamma hydroxybutyrate (GHB) is a nervous system depressant, that can produce both dose-related stimulant-like and sedative-like effects. Commonly considered a “club drug” or “party drug” (1,2), there is evidence that use is increasing among broader populations and contexts. Throughout Australia, there have been increases in GHB-related emergency department presentations (3,4,5), with some studies reporting high levels of methamphetamine co-detection. Withdrawal from GHB is comparable with that of alcohol withdrawal and when combined with methamphetamine use, the risk of seizures is elevated (4,6,7). The aim of this bulletin is to examine the characteristics and patterns of use of concomitant GHB and stimulant use within a sentinel group of people who inject drugs in Australia.