Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 17 3 2023 09 27 1646 1646 Seyedeh Zahra Parkhideh Department of Biology and Vector Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mehdi Forouzesh Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Maryam Akhgari Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Leila Bahmanabadi Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Farzaneh Jokar Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Samira Valiyari Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Kamran Akbarzadeh Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Sara Rahimi Medicinal Plants Research Center, Maragheh University of Medical Sciences, Maragheh, Iran Ali Mohammad Alimohammadi Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Sayena Rafizadeh Ministry of Health and Medical Education, Tehran, Iran Yavar Rassi Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2023 05 07 2023 06 13 Background: It is possible to identify drugs and poisons present in cadavers by analyzing blowfly larvae and pupae col­lected during forensic autopsies. The main purpose of this study was to use Lucilia sericata’s larvae and pupae to iden­tify drugs and poisons present in human cadavers. Methods: In an investigation, immature L. sericata fed meat treated with methamphetamine (MA) at various concentra­tions (45, 90, and 180 ng/mg) were analyzed to detect MA. Acetylation derivatization and liquid-liquid extraction (LLE) were used as sample preparation methods prior to gas chromatography-mass spectrometry (GC-MS) analytical instru­men­tation to find MA. Results: According to this study, L. sericata can be used in toxicological testing to identify MA in a host body. All L. seri­cata larval stages, particularly the third stage larva, pupa and empty pupa tested were positive for MA. Larvae in their first instar produced weak peaks. The L. sericata post-feeding instar following the 45 ng/mg treatment showed the highest MA concentration. For the first time, derivatization using the acetylation approach was used to prepare samples, and successfully, excellent results were obtained. Conclusion: Low quantities of MA can be easily found in immature fly samples using GC-MS. It is important to ana­lyze all samples including human tissues and insect samples, for postmortem drug testing. They can be utilized to find entire MA before they are excreted in excretory samples such as urine. Also, third instar larvae are a great and reliable sample for toxicological study. https://jad.tums.ac.ir/index.php/jad/article/view/1646 https://jad.tums.ac.ir/index.php/jad/article/download/1646/630