Pregabalin is the active ingredient of drugs used to treat neurosis, anxiety disorders, neuropathic pain. Due to severe stress, caused by genetic factors but mainly lifestyle, many patients currently suffer from anxiety disorders, and increasingly they are turning to this type of medication. Pregabalin taken in an uncontrolled manner can cause adverse side effects, and indirectly even lead to death. Pregabalin is also used in cats to alleviate anxiety and fear associated with veterinary visits and transport. Administered as an oral solution about 1.5 hours before a scheduled trip, it significantly reduces this anxiety. It is also used to reduce pain in dogs undergoing surgery and for the treatment of neuropathic pain. The purpose of this study was to investigate the effect of pregabalin on the length of the life cycle of Lucilia sericata (Meigen, 1826) (Diptera: Calliphoridae). A culture was carried out on a meat medium in the form of a dead laboratory mouse. Observations were carried out using different doses of the active substance (administered orally to the mice): 100 mg/kg (dose 1), 200 mg/ kg (dose 2) and 300 mg/kg (dose 3). A control sample (without the drug) was used for comparison. The results showed that pregabalin prolonged the life cycle of the fly relative to the control without the addition of the drug. In addition, it caused a decrease in the body weight of the larvae and pupae and increased their mortality relative to the control sample. By contributing to an understanding of the mechanism of bioaccumulation, this type of study provides valuable information for more accurate estimation of the time of death