[Chemical content of street cannabis].

Introduction: There is little information available about the real content of cannabis consumed in France.
Objective: To assess the chemical content, including adulterants and contaminants, and potency of cannabis samples obtained from end-users.
Methods: Samples of resins considered by users to produce "unusual" effects were collected from habitual consumers and chemically analyzed.
Results: Thirty-seven samples were obtained. Average THC content was 8.8%. The effects reported by users were consistent with the THC content. Apart from an unidentified fatty substance found in two samples, no adulteration was found.
Discussion: This study, which relied on volunteers, enabled us to collect samples considered abnormal by experienced users. It did not confirm the numerous anecdotes of adulteration.
Conclusion: We suggest that this study should be widened to monitor the current chemical contents of cannabis derivatives available in France. The impact of providing users with the results remains to be evaluated.