Background: Illicit drug use at festivals can cause an extensive burden on medical emergency services. This study investigated the prevalence of intoxications at a Belgian festival over 6 years and examined the influence of real-time drug alerts, after the detection of high-dose MDMA tablets by an on-site drug laboratory, introduced in 2022, on intoxication prevalence and first aid service use.

Methods: Demographic data and type of drug intoxication were collected retrospectively from festivalgoers who presented at the first aid service of a Belgian festival between 2018–2024. Presentation rate and transport-to-hospital rate were collected.

Results: In 6 years, 291667 attended the festival, 4086 of which attended on-site first aid and 362 of these presented intoxicated. Alcohol (49%, n = 178) and amphetamine (MDMA included) were most prevalent (37%, n = 133). The number of intoxications increased yearly and was highest in 2023 (77). In total, 24 real-time drug alerts were disseminated (2022-2024).

The proportion ‘unknown’ intoxication decreased after implementation of on-site drug testing 29.7% (n = 44) vs. 17.8% (n = 38), p = 0.008). The number of hospitalizations was similar 2% (n = 3) vs. 3.7% (n = 8), p = 0.35.

Conclusion: It might be that, after broadcasting real-time drug alerts, festival attendees might be more vigilant about drugs, however, the true impact remains unclear and might be influenced by other factors. The lack of power might underestimate the impact on hospitalizations.